Flexible robotic actuators

ABSTRACT

Systems and methods for providing flexible robotic actuators are disclosed. Some embodiments of the disclosed subject matter include a soft robot capable of providing a radial deflection motions; a soft tentacle actuator capable of providing a variety of motions and providing transportation means for various types of materials; and a hybrid robotic system that retains desirable characteristics of both soft robots and hard robots. Some embodiments of the disclosed subject matter also include methods for operating the disclosed robotic systems.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. Non-Provisionalpatent application Ser. No. 14/480,106, entitled “FLEXIBLE ROBOTICACTUATORS,” filed on Sep. 8, 2014, which is a continuation applicationof the International Application No. PCT/US2013/032297, entitled“SYSTEMS AND METHODS FOR PROVIDING FLEXIBLE ROBOTIC ACTUATORS,” filed onMar. 15, 2013, which claims benefit of the earlier filing date of U.S.Provisional Patent Application No. 61/615,665, entitled “FLEXIBLEROBOTIC ACTUATORS,” filed on Mar. 26, 2012; of U.S. Provisional PatentApplication No. 61/673,003, entitled “SYSTEMS AND METHODS FORINTEGRATION OF SOFT ROBOTS AND HARD ROBOTS,” filed on Jul. 18, 2012; andof U.S. Provisional Patent Application No. 61/698,436, entitled “SYSTEMSAND METHODS FOR PROVIDING SOFT TENTACLES,” filed on Sep. 7, 2012. Allpatents, patent applications and publications cited herein are herebyincorporated by reference in their entireties in order to more fullydescribe the state of the art as known to those skilled therein as ofthe date of the invention described herein.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

The present invention was made with United States government supportunder Grant No. W911NF-11-1-0094 and W911NF-09-1-0476 awarded by DefenseAdvanced Research Projects Agency (DARPA); under Grant No.DE-FG02-00ER45852 awarded by the Department of Energy; and under GrantNos. DMR-1005022, PHY-0646094, and DMR-0820484 awarded by NationalScience Foundation (NSF). The United States government has certainrights in this invention.

BACKGROUND

Many approaches to robots that resemble animals with skeletons are beingactively developed. Most of these robots are constructed using so-called“hard” body plans; that is, a rigid (usually metal) skeleton, electricalor hydraulic actuation, electromechanical control, sensing, andfeedback. These robots are successful at the tasks for which they weredesigned (e.g., heavy manufacturing in controlled environments.)However, these robots have severe limitations when faced with moredemanding tasks (for example, stable motility in demandingenvironments): tracks and wheels perform less well than legs and hoovesin many circumstances.

Another class of robots—those based on animals without skeletons—aremuch less explored, for a number of reasons: i) there is a suppositionthat “marine-like” organisms (squid) will not operate without thebuoyant support of water; ii) the materials and components necessary tomake these systems are often not available; iii) the major types ofactuation used in them (for example, hydrostats) are virtually unused inconventional robotics. These systems are intrinsically very different intheir capabilities and potential uses than hard-bodied systems. Whilethey will (at least early in their development) be slower thanhard-bodied systems, they will also be more stable and better able tomove through constrained spaces (cracks, rubble), lighter, and lessexpensive.

Robots, or robotic actuators, which can be described as “soft” are mosteasily classified by the materials used in their manufacture and theirmethods of actuation. The field of soft robotic actuation began withwork by Kuhn et al in 1950. Their work focused on the reversible changein the coiling and uncoiling of a polymeric material dependent on the pHof the surrounding medium. They used this to successfully raise andlower a weight, thus showing proof of principle for the use of softmaterials in robotic actuation. Hamlen et al expanded upon this idea in1965 and showed that polymeric materials can be made to contractelectrolytically. These two developments set the scene for future workusing the swelling of polymeric gels and electronic control ofdielectric-based actuators. Otake et al have demonstrated the use ofelectro-active polymers in the manufacture of starfish-shaped roboticactuators. Pneumatically-driven soft actuators based on pressurizationof sealed chambers fabricated from extensible polymers were firstreported by Suzumori et al in 1991. This type of actuation has been usedon the millimeter scale to fabricate grippers, tentacles, and otherrelated devices including pneumatic balloons.

Pneumatic soft robotic actuators can be manufactured using inextensiblematerials, which rely on architectures such as bellows. McKibbenactuators, also known as pneumatic artificial muscles (PAMs), rely onthe inflation of a bladder constrained within a woven sheath which isinextensible in the axis of actuation. The resultant deformation leadsto radial expansion and axial contraction; the force that can be appliedis proportional to the applied pressure. Related actuators are calledpleated pneumatic artificial muscles.

There are “soft” robotic actuators such as shape memory alloys whichhave been used by Sugiyama et al both as the actuation method and as themain structural component in robots which can both crawl and jump.Another approach, which can be described as “soft” uses a combination oftraditional robotic elements (an electric motor) and soft polymericlinkages based on Shape Deposition Manufacturing (SDM). This techniqueis a combination of 3D printing and milling. An example of a compositeof traditional robotics with soft elements has been used with greatsuccess in developing robotic grippers comprising soft fingers toimprove the speed and efficiency of soft fruit packing in New Zealand.

Additional capabilities for soft robotics are desired.

SUMMARY

Flexible robotic actuators and robotic systems formed using flexiblerobotic actuators are described. These and other aspects and embodimentsof the disclosure are illustrated and described below.

Some embodiments include a soft robot. The soft robot can include aflexible body having a plurality of embedded fluid channels, where atleast two of the plurality of embedded fluid channels are arrangedconcentrically around a central axis of the flexible body. The softrobot can also include a pressurizing inlet coupled to the at least twoof the plurality of embedded fluid channels, where the pressurizinginlet is configured to receive pressurized fluid to inflate a portion ofthe at least two of the plurality of embedded fluid channels, therebycausing a radial deflection of the flexible body.

In any of the embodiments described herein, the soft robot can alsoinclude a soft chamber disposed above and in sealing contact with theflexible body, wherein the soft chamber comprises a fluid reservoir anda fluid inlet.

In any of the embodiments described herein, the soft chamber comprises acap comprising a cover layer and one or more walls, wherein the one ormore walls are attached to the flexible body, and a volume between thecap and the flexible body forms the fluid reservoir.

In any of the embodiments described herein, the fluid reservoir isconfigured to deliver fluid via the fluid inlet when the at least two ofthe plurality of embedded fluid channels are pressurized.

In any of the embodiments described herein, the fluid reservoir isconfigured to receive fluid via the fluid inlet when the at least two ofthe plurality of embedded fluid channels are depressurized.

In any of the embodiments described herein, the flexible body is moldedusing an elastomer.

In any of the embodiments described herein, the at least two of theplurality of embedded fluid channels are arranged as concentricpolygons.

In any of the embodiments described herein, the concentric polygonscomprise concentric circles.

In any of the embodiments described herein, the flexible body caninclude a strain limiting layer, where a tensile modulus of the strainlimiting layer is higher than a tensile modulus of the flexible body.

In any of the embodiments described herein, the strain limiting layercomprises paper.

Some embodiments include a method of actuating a soft robot. The methodcan include providing a soft robot according to embodiments describedherein, and providing pressurized fluid to the pressurizing inlet topressurize the at least two of the plurality of embedded fluid channels,thereby causing a radial deflection of the soft robot.

Some embodiments include a method of actuating a soft robot. The methodcan include providing a soft robot according to embodiments describedherein, providing fluid to the soft chamber via the fluid inlet, andproviding pressurized fluid to the pressurizing inlet to pressurize theat least two of the plurality of embedded fluid channels, therebyexpelling fluid housed within the soft chamber via the fluid inlet.

In any of the embodiments described herein, the method can furtherinclude removing the pressurized fluid from the pressurizing inlet todepressurize the at least two of the plurality of embedded fluidchannels, thereby inhaling fluid into the soft chamber via the fluidinlet.

In any of the embodiments described herein, the soft chamber isconfigured to accommodate a chemical reagent capable of reaction with areagent to generate a color.

Some embodiments include a method of gripping a non-porous surface. Themethod can include providing a soft robot according to embodimentsdescribed herein, positioning the soft robot against a non-poroussurface, and providing pressurized fluid to the pressurizing inlet topressurize the at least two of the plurality of embedded fluid channels,thereby collapsing the soft robot against the non-porous surface to forma suction seal.

Some embodiments include a soft robotic actuator. The soft roboticactuator can include a flexible molded body having a plurality ofchannels disposed within the molded body, where the plurality ofchannels is coaxial with a central axis of the flexible molded body,where a portion of the molded body comprises an elastically extensiblematerial and a portion of the molded body is strain limiting relative tothe elastically extensible material, and where the molded body isconfigured to preferentially expand when one of the plurality ofchannels is pressurized by pressurized fluid. The soft robotic actuatorcan also include at least one pressurizing inlet that is configured toreceive pressurized fluid for at least one of the plurality of channels.The soft robotic actuator can further include a first transport channelconfigured to transfer a first material between one end of the flexiblemolded body and the other end of the flexible molded body, and a secondtransport channel configured to transfer a second material between oneend of the flexible molded body and the other end of the flexible moldedbody.

In any of the embodiments described herein, the first transport channelis embedded in the strain limiting portion of the molded body, and thesecond transport channel is embedded in the elastically extensibleportion of the flexible molded body.

In any of the embodiments described herein, the first material comprisessolid particles and the second material comprises liquid.

In any of the embodiments described herein, the first material comprisessolid particles and the second material comprises liquid.

In any of the embodiments described herein, the plurality of channels issectioned along the central axis of the molded body to provide complexmotions.

Some embodiments include a soft robotic system. The soft robotic systemcan include a plurality of flexible actuators configured to support thesoft robotic system, where at least one of the flexible actuatorscomprises a fluidic channel that is configured to be pressurized toactuate the associated flexible actuator. The soft robotic system canalso include a soft tentacle actuator comprising a flexible molded bodyhaving a plurality of channels disposed within the molded body, wherethe plurality of channels is coaxial with a central axis of the flexiblemolded body, where a portion of the molded body comprises an elasticallyextensible material and a portion of the molded body is strain limitingrelative to the elastically extensible material, and where the moldedbody is configured to preferentially expand when one or more of theplurality of channels is pressurized by pressurized fluid. The softrobotic system can further include a camera module coupled to theflexible molded body, configured to capture an image of a scenesurrounding the soft robotic system.

In any of the embodiments described herein, the plurality of flexibleactuators is configured to be actuated in response to the image capturedby the camera module.

In any of the embodiments described herein, the soft tentacle actuatorand the plurality of flexible actuators are configured to beindependently actuated.

Some embodiments include a robotic system. The robotic system caninclude a soft robot system comprising a flexible body having aplurality of embedded fluid channels, where the plurality of embeddedfluid channels is defined by upper, lower and side walls, where at leastone wall is strain limiting, where the soft robot further comprises apressurizing inlet coupled to the plurality of embedded fluid channels,and where the pressurizing inlet is configured to receive pressurizedfluid to pressurize at least a portion of the plurality of embeddedfluid channels to cause a movement of the soft robot. The robotic systemcan also include a hard robot coupled to the soft robot, configured toprovide locomotion to the robotic system. The robotic system can furtherinclude a robotic control system coupled to the soft robot and the hardrobot, where the robotic control system comprises a fluidic systemconfigured to provide the pressurized fluid to the fluid inlet.

In any of the embodiments described herein, the fluidic system includesa pump and a valve coupled to the pressurizing inlet of the soft robotsystem, configured to pressurize one or more of the plurality of fluidchannels, and wherein the pump and the valve are configured to becontrolled using an actuation sequence associated with the one or moreof the plurality of fluid channels.

In any of the embodiments described herein, the actuation sequenceindicates at least one of (a) closing the valve, (b) turning on the pumpto pressurize the fluid channel, (c) turning off the pump while keepingthe valve closed, and (d) opening the valve to deflate the fluidchannel.

In any of the embodiments described herein, the soft robot systemcomprises the soft robot, the soft robotic actuator, or any other typesof flexible robotic systems.

In any of the embodiments described herein, the soft robot systemcomprises a plurality of actuators, where in each of the plurality ofactuators has a fluid inlet.

In any of the embodiments described herein, the fluidic system isconfigured to provide motion to the soft robot system by selectivelyactuating one or more of the actuators using an actuation sequenceassociated with the actuators.

In any of the embodiments described herein, the plurality of actuatorsin the soft robot are arranged to exhibit a rotational symmetry.

In any of the embodiments described herein, the robotic control systemis configured to modify a motion direction of the soft robot system bymodifying an association between the actuation sequence and theactuators.

In any of the embodiments described herein, the robotic system furtherincludes a central control system coupled to the robot control system,the central control system is configured to instruct the robot controlsystem to cause the hard robot to move in a predetermined manner.

In any of the embodiments described herein, the robotic system furtherincludes a camera system coupled to the central control system, wherethe camera system is configured to record an image of an environmentsurrounding the hard robot, and where the central control system isconfigured to use the recorded image to identify obstacles surroundingthe hard robot.

In any of the embodiments described herein, the soft robotic system isconfigured to be actuated in response to the image captured by thecamera system.

In any of the embodiments described herein, the robotic system includesa robotic vacuum cleaner.

Some embodiments include a method of operating a robotic system. Themethod can include providing a robotic system as disclosed in any of theembodiments described herein, receiving, by a central control systemfrom a camera system, an image of a scene surrounding the hard robot,identifying, by the central control system, an object to be grabbed bythe soft robot system, and instructing, by the central control system,the robotic control system to cause the hard robot to move to a locationproximate to the identified object and the soft robot system to grab theidentified object.

In any of the embodiments described herein, the method can furtherinclude providing, by the robotic control system, an actuation sequenceto the fluidic system to control the soft robot system.

In any of the embodiments described herein, the fluidic system comprisesa pump and a valve, and wherein the method further comprises (a) closingthe valve, (b) turning on the pump to pressurize the fluid channel, (c)turning off the pump while keeping the valve closed, and (d) opening thevalve to deflate the fluidic channel.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described with reference to the following figures,which are presented for the purpose of illustration only and are notintended to be limiting.

FIGS. 1A-1C illustrate principles of fluidic actuation of a soft robotin accordance with certain embodiment.

FIGS. 2A-2E illustrate a soft tentacle and its operation in accordancewith some embodiments of the disclosed subject matter.

FIG. 3 illustrates a relationship between stress and strain for Ecoflexin accordance with some embodiments of the disclosed subject matter.

FIGS. 4A-4F illustrate a control of a soft tentacle's bending directionin accordance with some embodiments of the disclosed subject matter.

FIG. 5 illustrates individual parts of a mold in accordance with someembodiments of the disclosed subject matter.

FIGS. 6A-6D illustrate the size of individual parts of a mold inaccordance with some embodiments of the disclosed subject matter.

FIG. 7 illustrates a process of assembling a mold for a soft tentacle inaccordance with some embodiments of the disclosed subject matter.

FIG. 8 illustrates a cross section of a mold for a soft tentacle inaccordance with some embodiments of the disclosed subject matter.

FIGS. 9A-9C illustrate the process of fabricating a soft tentacle usinga mold in accordance with some embodiments of the disclosed subjectmatter.

FIGS. 10A-10B illustrate a process of fabricating a soft tentacle usinga plastic extrusion technique in accordance with some embodiments of thedisclosed subject matter.

FIGS. 11A-11C illustrate the process of inserting a tubing into anelastomeric wall in accordance with some embodiments of the disclosedsubject matter.

FIGS. 12A-12B illustrate structures for coupling a pressurized gassource to a gas inlet in accordance with some embodiments of thedisclosed subject matter.

FIGS. 13A-13D illustrate a container with a textured internal surface inaccordance with some embodiments of the disclosed subject matter.

FIGS. 14A-14G illustrate a soft tentacle with a textured surface and itsoperation in accordance with some embodiments of the disclosed subjectmatter.

FIGS. 15A-15D illustrate a design and fabrication of a multi-sectionsoft tentacle in accordance with some embodiments of the disclosedsubject matter.

FIGS. 16A-16D illustrate a variety of shapes that can be formed using amulti-section soft tentacle in accordance with some embodiments of thedisclosed subject matter.

FIGS. 17A-17H illustrate a fluid delivery robot and its application inaccordance with some embodiments of the disclosed subject matter.

FIGS. 18A-18D illustrate a transfer of solid materials using a softtentacle in accordance with some embodiments of the disclosed subjectmatter.

FIGS. 19A-19B illustrate a soft tentacle with a plurality of transportchannels in accordance with some embodiments of the disclosed subjectmatter.

FIGS. 20A-20D illustrate a transfer of dissolved particles using a softtentacle in accordance with some embodiments of the disclosed subjectmatter.

FIGS. 21A-21E illustrate a suction robot and its operation in accordancewith some embodiments of the disclosed subject matter.

FIG. 22 illustrates a soft tentacle with a camera module in accordancewith some embodiments of the disclosed subject matter.

FIG. 23 illustrates a soft tentacle that includes a needle in accordancewith some embodiments of the disclosed subject matter.

FIG. 24A-24D shows a soft-tentacle having a camera, mounted on top of aquadruped in accordance with some embodiments of the disclosed subjectmatter.

FIGS. 25A-25C illustrate a radial deflection actuator in accordance withsome embodiments of the disclosed subject matter.

FIG. 26 illustrates a mold for molding the radial deflection actuator inaccordance with some embodiments of the disclosed subject matter.

FIGS. 27A-27C illustrate using the radial deflection actuator as agripping device in accordance with some embodiments of the disclosedsubject matter.

FIGS. 28A-28C demonstrate a manipulation of an object, e.g., a petridish, using a radial deflection actuator in accordance with someembodiments of the disclosed subject matter.

FIGS. 29A-29D illustrate a cross-section of a fluid suction device inaccordance with some embodiments of the disclosed subject matter.

FIG. 30 shows a mold for molding a layer of soft material for a softchamber in accordance with some embodiments of the disclosed subjectmatter.

FIGS. 31A-31D demonstrate a manipulation of dyed water using a fluidsuction device in accordance with certain embodiments.

FIGS. 32A-32C demonstrate the use of the fluid suction device in achemical analysis application, in accordance with certain embodiment.

FIG. 33 illustrates a robotic system integrating a soft robot and a hardrobot in accordance with certain embodiments of the disclosed subjectmatter.

FIG. 34 illustrates the actuators configured as a walker and a roboticcontrol system coupled to the walker in accordance with certainembodiments of the disclosed subject matter.

FIGS. 35A-35B illustrate the walking motion of the walker in accordancewith certain embodiments of the disclosed subject matter.

FIGS. 36A-36D illustrate the paddling motion of the leg in accordancewith certain embodiments of the disclosed subject matter.

FIGS. 37A-37C illustrate the design and the deployment of a bump sensorin accordance with certain embodiments of the disclosed subject matter.

FIGS. 38A-38D illustrate a soft robot, soft robot actuation sequences,and fluidic pumps and valves in accordance with certain embodiments ofthe disclosed subject matter.

FIG. 39 illustrates the directional walking movements of the soft robotin accordance with certain embodiments of the disclosed subject matter.

FIGS. 40A-40B illustrate the robotic vacuum cleaner in accordance withcertain embodiments of the disclosed subject matter.

FIG. 41 illustrates a process of moving an object using a robotic moverin accordance with some embodiments of the disclosed subject matter.

DETAILED DESCRIPTION

Organisms, such as Echinoderms (starfish, sea urchins) and Cnidarians(jellyfish) are ancient and incredibly successful, relatively simpleorganisms capable of movement unheard of in even the most advancedhard-robotic systems. One major reason for the gap between nature andthe state of the art robotic systems is the severe limitation inmaterial selection available for robotics.

To bridge this gap between natural and the state of the art roboticsystems, robotic systems have exploited different materials. Forexample, a soft robotic system can use soft materials, such as softelastomer, or flexible materials, such as papers and a nitrile, to buildits structures, as disclosed in PCT Patent Application No.PCT/US2011/061720, titled “Soft robotic actuators,” and PCT PatentApplication No. PCT/US2013/022593, titled “Flexible robotic actuators,”which are hereby incorporated by reference in its entirety.

Generally, “soft” robots—robots having flexible components that providemultiple degrees of freedom—have many useful capabilities. Thesecapabilities include the abilities to deform their shape, to manipulatedelicate objects, to conform to their surroundings, and to move incluttered and/or unstructured environments. The flexibility of softactuators can offer potentially useful approaches to problems inrobotics, and to the design of actuators. They can also take advantageof often highly non-linear responses to actuation to accomplish,relatively simply, types of complex motions and tasks that are moredifficult to accomplish using hard machines and conventionalcontrollers. Soft robots based on flexible elastomers, as one simpleexample, can distribute pressure over large areas without elaboratecontrols; this capability makes it possible for them to manipulatefragile and irregular objects. In this type of design, the robot canperform complex motions only with a single pressure source; theappropriate distribution, configuration, and size of the pressurizednetworks, in combination with a sequence of actuation of specificnetwork elements, can determine the resulting movement.

The present disclosure provides additional capabilities to soft roboticsystems and provides mechanisms for integrating soft robotic systemswith hard robotic systems. These additional capabilities and mechanismscan be employed alone, or in combination with other soft roboticactuators such as those referred to in the previous paragraph.

The disclosed subject matter includes a soft tentacle. The disclosedsoft tentacle can provide a variety of motions. For example, the softtentacle can provide a simple rolling motion. As another example, thesoft tentacle can provide a complex three-dimensional motion based on anindependent control of local curvatures along the tentacle. In someembodiments, these complex motions can be used to grab and manipulateobjects with complex shapes and various surface characteristics, such asthe surface resistance. In other embodiments, the soft tentacle can beemployed in conjunction with other functional modules to provideadditional capabilities. The functional modules can include a needle fordelivering fluid, a camera modules for capturing images/videos, or asuction cup for lifting and moving objects. In other embodiments, thesoft tentacles' surface can be textured to improve, for example, theiradhesion to slippery surfaces.

The disclosed subject matter also includes a radial deflection actuatorthat is capable of out of plane deflection around a central point, e.g.,movement from a planar configuration at a resting position to a convexor hemispherical position in an actuated position. Such a deflection isreferred to herein as a “radial deflection.” Radial deflections can beuseful in soft robots because the radial deflection provides a suctionmechanism. The suction mechanism can be used in many applications,including, as disclosed below, gripping of objects, reversibleattachment of robots to surfaces, collection/delivery of fluids, andchemical sample collection for direct or down-stream chemical analysis.

The disclosed subject matter also includes a hybrid robotic system thatintegrates one or more multifunctional soft robots and hard robots.While soft robots can perform many types of complex motions, even themost sophisticated soft robots may be challenged by tasks that hardrobots can easily address. The hybrid robotic system can operate thesoft robot and the hard robot to retain desirable features of bothrobots. For example, the robotic system can use the hard robot to moveacross a long distance on a flat terrain, and the robotic system can usea soft robot to perform tasks within a smaller region with a ruggedsurface.

Actuation Principles of Soft Robots

In some embodiments, a soft robot actuator can be actuated usingpressurized fluid (i.e., pressurized gas or liquid.) The principle offluidic actuation is illustrated in FIGS. 1A-1C, in which channel 100 isembedded in a soft rubber (elastomeric) form 102 having a stiffer, yetstill pliable backing layer 104. A material with a high elastic modulusis sought for materials used for sections of the network where inflationis undesirable, while a material with a low elastic modulus is used formaterials of the network where extensibility is needed. Uponpressurization of the channel via pressurized fluid (e.g., pressurizedgas and/or liquid), the soft-elastomer network expands (FIG. 1B).Specifically, when pressurized, channel will expand in the region 106that is the most extensible. To accommodate the increased volume thatresults when the channel expands like balloons, the structure bends inresponse. The soft-rubber's expansion is accommodated by bending aroundthe stiffer, strain limiting layer (FIG. 1C). Further detail regardingthe actuating principle of channels or chambers embedded in elastomericbodies, is described in “Soft robotic actuators,” filed on Nov. 21,2011, identified as PCT Application No. PCT/US2011/061720, which isherein incorporated by reference in its entirety.

As used herein, “stiffness” refers to the resistance of the elastic bodyto deformation (e.g., extension) by an applied force. In general,elastic modulus is related to, but not the same as, stiffness. Elasticmodulus is a property of the constituent material; stiffness is aproperty of a structure. That is, the elastic modulus is an intensiveproperty of the material; stiffness, on the other hand, is an extensiveproperty of the network and is dependent on the material modulus and theshape and boundary conditions. Because stiffness is a function of theYoung's modulus, the material modulus can be used as a comparativemeasure of the relative stiffness of the channels walls and a predictorof deflection upon pressurization of the channel networks.

Strain is a description of deformation in terms of relative displacementof a body. A deformation results from a stress induced by appliedforces, in the case here, for example, by the pressurizing force.Because materials of lower stiffness or smaller elastic modulus willdeform to a greater degree than the higher elastic modulus materials,the low stiffness materials experience strain or deformation first. As aresult, the strain in the material of higher stiffness or greaterelastic modulus is smaller or “limited.” As used herein, the layer orwall of the channel that is stiffer, e.g., has a higher elastic modulus,is referred herein to the “strain limiting” layer or wall or membrane.

Soft Tentacle Actuators

A soft tentacle actuator can have at least four characteristics thatmake it especially suited for soft robotic applications: i) thedisclosed soft tentacle is light, with a mass of 100 grams per meter;ii) the disclosed soft tentacle is compatible with high-speed actuation(e.g., complete activation in ˜0.5 second using gas at 300 millibar,delivered through a 25-cm long tether with an internal diameter of 1.57mm); iii) the disclosed soft tentacle is resistant to damage from impactand fall; and iv) the disclosed soft tentacle is compatible with theintroduction of components with specialized optical, electrical, ormechanical functions, and with the modification of its surface toimprove its interaction with objects.

Structure and Characteristics of Soft Tentacle Actuator

FIGS. 2A-2E illustrate a soft tentacle and its operation in accordancewith some embodiments of the disclosed subject matter. FIG. 2A shows asoft tentacle 202, fluidic channels 204 in the soft tentacle, and thegas inlets 206 coupled to the fluidic channels 204. In some embodiments,the fluidic channels 204 can be coaxial with the soft tentacle, and runalong the length of the soft tentacle. The total length of the tentacleillustrated in FIG. 2A is about 15 cm. The length of the fluidicchannels can be 14 cm, starting at a position separated from the root ofthe tentacle by 5 mm. However, the length of the tentacle and the lengthof the fluidic channels can be of any desired length.

In some embodiments, the soft tentacle 202 can include a core structure208 and a skin structure. The core structure 208 can be strain limitingrelative to the skin structure. In other words, the core structure 208can be formed using a stiffer material than that of the skin structure.As illustrated in FIG. 2A, the core structure 208 can be formed usingpolydimethylsiloxane (PDMS) and the skin structure can be formed usingEcoflex. The core structure 208 can have any suitable shapes. Forexample, the core structure 208 can have a cylindrical shape, a cuboidshape, a triangular prism shape, a hexagonal prism shape, or any otherpolygonal prism shapes that are suitable for desired applications.

The soft tentacle 202 can be actuated by fluidic pressure applied to thefluidic channels 204 via the gas inlets 206. The gas inlets 206 includethree nozzles, each of which can be coupled to one of the fluidicchannels 204. In some embodiments, each nozzle can be coupled to anindependent pressure source, which can allow for an independentactuation of the fluidic channels 204. In other embodiments, each nozzlecan be coupled to the same pressure source, which allows for asimultaneous actuation of the fluidic channels 204.

FIG. 2B illustrates a structural deformation and a stress distributionin a fluidic channel upon pressurization, in accordance with someembodiments of the disclosed subject matter. Upon pressurization, afluidic channel 204 can expand in regions that are most compliant, orregions fabricated using a material with a lower stiffness compared toneighboring regions (i.e., the regions fabricated in Ecoflex). Forexample, an expansion of the fluidic channel 204 can thin the Ecoflexskin structure that is not in contact with the PDMS core structure.

As the applied pressure is increased, from atm P_(atm) to P_(III) theEcoflex skin structure can become thinner. In FIG. 2B, P_(I) correspondsto 75 millibar (mbar), P_(II) corresponds to 149 mbar, and P_(III)corresponds to 231 mbar. The thinning of the skin structure can beaccompanied by an asymmetric elongation of the two opposite walls of thefluidic channels 204. When the applied pressure is sufficiently high(e.g., around 230 millibar), the Ecoflex skin structure in the vicinityof the fluidic channels 204 can undergo a snap-through instability anddeform dramatically. This deformation can trigger the soft tentacle 202to bend. The extent to which the tentacle bends can be controlled bycontrolling the pressure applied to the fluidic channels 204. FIG. 2Cillustrates the bending of the soft tentacle in accordance with someembodiments of the disclosed subject matter. As the amount of pressureapplied to the fluidic channel increases, the extent to which thetentacle bends can also increase correspondingly.

In some embodiments, upon pressurization, the soft tentacle 202 canstart bending at the tail-end of the tentacle. In many cases, the forceto initiate the deformation at the tail end is smaller than the force toinitiate the deformation at the center of the tentacle. Therefore, asillustrated in FIG. 2C, as the pressure applied to the fluidic channel204 increases, the bending of the soft tentacle 202 would start at thetail-end of the tentacle. This structure-selective, regional actuationis one of the many useful non-linearities for generating complexmotions.

Once the tail-end of the soft tentacle 202 reaches the snap-throughinstability, the deformation at the end of the fluidic channels 204 canreach a saturation point. Upon reaching the saturation point, thebending motion can propagate towards the root of the tentacle, which cantrigger the tentacle to bend in a circular pattern (multiple times, ifit is sufficiently long), as illustrated in FIG. 2C.

The dependency of the tentacle's curvature and the pressure applied tothe fluidic channel can be characterized a numerical simulation.Although an analytical description of expanding thin-walled balloons iswell developed, an analytical description of a composite structure, suchas the soft tentacle, is not yet available. To address this issue,characteristics of an expanding fluidic channel can be simulated usingfinite element analysis.

The finite element analysis can include building a three-dimensionalmodel of an expanding fluidic channel using a finite element software.The finite element software can include ABAQUS of Dassault Systemes. Thethree-dimensional model of an expanding fluidic channel can include amodel of a snap-through instability. The model of a snap-throughinstability can include the Riks method. The Riks method can includemodeling the materials used to build the fluidic channel. To this end,the disclosed finite element analysis models the PDMS as anincompressible Neo-Hookean material with shear modulus G=1.84 MPa;Ecoflex can be modeled as an Arruda-Boyce material, i.e., a rubbermaterial that stiffens at a high strain in order to capture thesnap-through instability. FIG. 3 illustrates the relationship betweenstress and strain for Ecoflex under a uni-axial tension, in accordancewith some embodiments of the disclosed subject matter. The experimentalrelationship between stress and strain of Ecoflex is fitted as anincompressible Arruda-Boyce material with shear modulus G=0.03 MPa andλ_(lim)=3.9.

The model illustrated in the previous paragraph can be used to simulatethe dependency between the tentacle's curvature and the pressure appliedto the fluidic channel. FIG. 2D illustrates the simulated dependencybetween the tentacle's curvature and the pressure applied to the fluidicchannel, and FIG. 2E illustrates the experimental dependency between thetentacle's curvature and the pressure applied to the fluidic channel. Asillustrated by FIGS. 2D-2E, the simulated dependency closely tracks theexperimental dependency, thereby confirming the accuracy of the finiteelement analysis.

In some embodiments, the bending direction of the tentacle can becontrolled by controlling the pressure level of individual fluidicchannels 204. FIGS. 4A-4F illustrate how a bending direction of the softtentacle can change as a function of the pressure level of fluidicchannels, in accordance with some embodiments of the disclosed subjectmatter. Each row of FIGS. 4A-4F illustrates the bending direction of thetentacle when different one of the fluidic channels is pressurized. Forexample, FIG. 4B illustrates the bending of the tentacle when thefluidic channel 204 a is pressurized; FIG. 4D illustrates the bending ofthe tentacle when the fluidic channel 204 b is pressurized; and FIG. 4Fillustrates the bending of the tentacle when the fluidic channel 204 cis pressurized. Each column of FIGS. 4B, 4D, and 4F shows the extent towhich the tentacle bends as the applied pressure is increased. In FIGS.4B, 4D, and 4F, P_(I) corresponds to 75 mbar, P_(II) corresponds to 130mbar, and P_(III) corresponds to 270 mbar. Collectively, FIGS. 4A-4Fillustrate that the bending direction of the tentacle depends on thepressure level of the individual fluidic channels.

Fabrication

In some embodiments, the soft tentacle 202 can be fabricated using amold. The mold can be designed using a computer-aided design (CAD) tool,for example, from Alibre Inc. The designed mold can be generated using athree-dimensional (3D) printer, for example, StrataSys Dimension Eliteprinters. The mold can be printed with an acrylonitrile butadienestyrene (ABS) plastic.

In some embodiments, the mold can be built as individual pieces that canbe later assembled to form the mold. FIG. 5 illustrates individual partsof a mold in accordance with some embodiments of the disclosed subjectmatter. A mold can include a mold base 302, a core structure template304, fluidic channel templates 306, and a container 308. The partsillustrated in FIG. 5 are built in an acrylonitrile butadiene styrene(ABS) plastic using a three-dimensional printer. FIGS. 6A-6D illustratethe size of individual parts of a mold in accordance with someembodiments of the disclosed subject matter. FIG. 6A illustrates thedimensions of the mold base; FIG. 6B illustrates the dimensions of thecore structure template; FIG. 6C illustrates the dimensions of thefluidic channel template; and FIG. 6D illustrates the dimension of thecontainer used to contain the elastomers during the molding process. Theshape of the container determines the external shape of the fabricatedtentacle. As illustrated in FIG. 6D, the container can have acylindrical shape. The container can have a variety of other shapes,including a cuboid shape, a triangular prism shape, a hexagonal prismshape, or any other polygonal prism shapes that are suitable for desiredapplications. The dimensions illustrated in FIGS. 6A-6D are forillustrative purposes only. The individual parts of the mold can beformed in various sizes and lengths that are suitable for particularapplications of a soft tentacle.

FIG. 7 illustrates the process of assembling a mold 300 from theindividual parts in accordance with some embodiments of the disclosedsubject matter. In step i), a mold base 302 can be provided. In step 2,a core structure template 304 can be affixed on the mold base 302. Instep iii), fluidic channel templates 306 can be affixed on the mold base302, and in step iv), a container can be affixed on the mold base 302.

FIG. 8 illustrates a cross section of the assembled mold in accordancewith some embodiments of the disclosed subject matter. The corestructure template 304 and the fluidic channel templates 306 can occupythe volume for the core structure 208 and the fluidic channels 204 for asoft tentacle. In some embodiments, the core structure template 304 canbe substantially thicker than the fluidic channel templates 306. Forexample, the core structure template can have a thickness of 4 mm andthe fluidic channel templates can have a thickness of 800 μm. Theinternal diameter of the mold can control the thickness of thefabricated soft tentacle. The internal diameter of the mold 300 can be12 mm.

In some embodiments, the number of fluidic channels in the softtentacles can be controlled by controlling the number of fluidic channeltemplates in the mold. In some embodiments, the mold can include 2, 4,5, 6, or and other number of fluidic channel templates to form thecorresponding number of fluidic channels in a soft tentacle. In someembodiments, the mold templates can be symmetrically arranged around therotation axis so that the tentacle can be uniformly actuated uponpressurization. In some cases, the rotation axis of the tentacle can becharacterized as a straight line around which all fixed points of arotating tentacle move in circles. For example, if a tentacle has acylindrical shape, the rotation axis of the tentacle can be a set ofpoints corresponding to the center of the tentacle's cross sections.

FIGS. 9A-9C illustrate the process of fabricating a soft tentacle usinga mold in accordance with some embodiments of the disclosed subjectmatter. The soft tentacle can be built using soft materials such aselastomers. The elastomers can include Ecoflex and polydimethylsiloxane(PDMS). Ecoflex can be prepared using the following procedure. Ecoflexprecursor, such as Ecoflex 00-30 precursor, can be obtained fromSmooth-On (http://www.smooth-on.com). The obtained Ecoflex precursor canbe mixed in a 1:1 ratio by volume and the resulting prepolymer can bedegassed in a desiccator at 36 Torr for 5 minutes in order to remove airbubbles. Subsequently, the Ecoflex can be cured at 60° C. for about 15to 30 minutes. PDMS can be prepared using the following procedure. PDMSprecursors can be obtained from Dow Corning. The PDMS precursors can bemixed with a cross-linking agent at the ratio of 10:1 by weight. Theresulting prepolymer mixture can be degassed at 36 Torr for 30 minutesto remove any air bubbles and to ensure that the precursors and thecross-linking agent are mixed well. The prepolymer mixture can be curedat 60° C. for 2 hours. This curing time can assure a good bond betweenthe resulting PDMS and Ecoflex when PDMS is cured in contact withEcoflex.

Once Ecoflex and PDMS have been prepared, the soft tentacle can befabricated using the process illustrated as follows. The first stepincludes, as illustrated in FIG. 9A, filling the mold 300 with Ecoflexand curing the Ecoflex at 60° C. for 15 minutes. The second stepincludes cooling the Ecoflex to a room temperature and removing thecentral channel template, thereby forming an empty volume at the core ofthe Ecoflex. The third step, as illustrated in FIG. 9B, can includepouring PDMS into the empty volume and curing the PDMS at 60° C. for twohours so that PDMS and Ecoflex can bond together. The fourth stepincludes removing the composite structure from the mold by gentlypulling the composite structure. FIG. 9C illustrates the resultingcomposite structure. The resulting composite structure has fluidicchannels parallel to the central PDMS core structure 208. The last stepof fabrication includes sealing the two ends of the composite structureto form a soft tentacle. In some cases, sealing the two ends of thecomposite structure can include sealing the two ends using Ecoflexprepolymer. Sealing the two ends using Ecoflex prepolymer can includecuring the Ecoflex prepolymer at 60° C. for 15 minutes.

The illustrated molding process permits fabrication of devices having anoverall thickness greater than 1 mm and typically having a thickness inthe range of 5 mm to 5 cm. Exemplary thicknesses include 2-4 mm, 5 mm, 1cm, 2 cm, or 5 cm. The relatively large scale of the pressurizablenetworks (compared to features obtainable, for example, by conventionalphotolithographic techniques) result in the fabrication of functionaldevices on a large scale. Embedded channel networks in soft robotics arenot limited to large scale and it is contemplated that conventionalmicrofabrication techniques can be used to develop soft robotics on thesub-millimeter scale.

In some embodiments, a soft tentacle can be fabricated using a plasticextrusion technique. FIGS. 10A-10B illustrate a process of fabricating asoft tentacle using a plastic extrusion technique in accordance withsome embodiments of the disclosed subject matter. FIG. 10A illustrates aplastic extrusion machine 1002, and FIG. 10B illustrates a cross sectionof the plastic extrusion machine 1002. A plastic extrusion machine 1002can transform a polymer into a solid structure. This process can include(1) providing a polymer in liquid or viscous form to the hopper 1004,(2) pushing the liquid/viscous polymer through a tube 1006 along thespace between the tube 1006 and the central screw 1008 using a screwdriver motor 1010, (3) curing the polymer until the polymer is “about tobecome” solid, and (4) providing the polymer to a die 1012 having adesired shape in which the polymer is completely cured and takes thedesired shape. The die 1012 can have a negative imprint of the desiredtentacle structure. For example, the die 1012 can take the shape of themold in FIG. 7. In some cases, the curing step can include one or moreof: lowering the temperature of the polymer, applying heat to thepolymer selectively, mixing the polymer with curing agents, exposing thepolymer to oxygen and/or other gases, exposing the polymer to aultra-violet radiation, and exposing the polymer to catalysts. Thepolymer can include prepolymer, polyacrylates, polyurethane, resin, gum,and/or rubber.

In some embodiments, fluidic channels 204 can be pressurized via gasinlets 206. The gas inlets 206 can be coupled to the fluidic channels204 via a tubing. In some embodiments, the tubing can be formed usingpolyethylene. To couple the tubing with the fluidic channels 204, thetubing can be inserted into the elastomeric wall of a soft tentacle.FIGS. 11A-11C illustrate the process of inserting a tubing into anelastomeric wall in accordance with some embodiments of the disclosedsubject matter. As illustrated in FIGS. 11A and 11B, a cannula and atubing can be provided. The internal diameter of the cannula can begreater than the external diameter of the tubing so that the tubing canfit within the cannula. In some embodiments, the internal diameter ofthe cannula is 1.65 mm, and the external diameter of the tubing is 1.62mm, but any other sizes of cannula and/or tubing can be used. Asillustrated in FIG. 11C, inserting a tubing into an elastomeric wall caninclude inserting a cannula into the elastomeric wall, inserting atubing into the cannula so that the tubing can pass through theelastomeric wall, and then removing the cannula. Because the elastomericwall is soft, the elastomeric wall can wrap around the tubing to form anair-tight seal.

In some embodiments, the gas inlets 206 can be formed using a needle.The needle can be tightly coupled to the tubing to provide pressurizedgas to the fluidic channels 204. FIGS. 12A-12B illustrate structures forcoupling a pressurized gas source to a gas inlet in accordance with someembodiments of the disclosed subject matter. In some cases, thepressurized gas can be provided by a syringe 1202, as illustrated inFIG. 12A in accordance with some embodiments of the disclosed subjectmatter. The needle can simply be coupled to the syringe 1202 to receivepressurized gas. In other cases, the pressurized gas can be provided bya gas source 1204, as illustrated in FIG. 12B in accordance with someembodiments of the disclosed subject matter. The needle can be coupledto a connector 1206, which is further coupled to a hose that can receivepressurized gas from the gas source 1204.

In some embodiments, the core structure 208 can include tethers forfunctional modules coupled to the soft tentacle. As illustrated below,the soft tentacle can be coupled to other functional modules, includinga suction module, a camera, and medical apparatuses. The core structure208 can be used to embed the tethers for coupling the functional modulesto the soft tentacle and/or external devices, such as computers. Thetethers can include a power line for delivering power to the functionalmodules, or fluidic channels for controlling the functional modules.

Applications

A soft tentacle can be used in a variety of applications. Oftentimes,the soft tentacle can interact with other objects by contacting theobjects with the tentacle's skin. For example, the soft tentacle can beused to grab objects by wrapping the tentacle around the object ofinterest and lifting the tentacle.

In some embodiments, a soft tentacle's skin structure can be tailored toa certain application to enhance the tentacle's interaction with otherobjects. For example, when a soft tentacle is to be used for grabbingsmooth or slippery objects, the surface of the tentacle can be texturedto improve the grip. In some cases, the surface of the tentacle can bemanipulated by modifying the mold used to fabricate the tentacle. FIGS.13A-13D illustrate a container with a textured internal surface forfabricating a tentacle with a bellows skin structure in accordance withsome embodiments of the disclosed subject matter. The tentacle with abellows skin structure can be more compliant than a flat surface of thesame material, and can also provide more traction. FIG. 13A illustratesan external view of the container 1302, which may not exhibit anydifferences from a container without a textured internal surface. FIG.13B illustrates the internal surface of the container 1302. The internalsurface can have the bellows structure 1304 that would form the bellowsstructure on the surface of the tentacle. FIGS. 13C-13D illustrate thedimensions of the container 1302: FIG. 13C shows dimensions of thecross-section of the container 1302; FIG. 13D shows dimensions of theperspective view of the container 1302. These dimensions are forillustrative purposes only. The container, as well as the bellowsstructure in the container, can be formed in various sizes that aresuitable for particular applications of the resulting tentacle.

FIGS. 14A-14G illustrate a soft tentacle with a textured surface and itsoperation in accordance with some embodiments of the disclosed subjectmatter. As illustrated in FIG. 14A, the textured soft tentacle 1402 caninclude a bellows structure on its surface. FIG. 14B illustrates thebellows structure on the surface at a higher zoom. In some embodiments,the textured tentacle can be more compliant than a flat-surface tentaclehaving the same thickness because the textured tentacle has less amountof elastomer for its skin structure compared to that of the flat-surfacetentacle and because each ridge on the textured surface can furtherassist the deformation of the tentacle.

A textured soft tentacle can grab objects better than a flat-surfacesoft tentacle. For example, the textured soft tentacle can grab a flatwrench coated with gelatin, as illustrated in FIGS. 14C-14F, which canbe challenging for a flat-surface soft tentacle because the gelatincoating is slippery. FIG. 14G illustrates, in a close-up view, how thetextured soft tentacle grabs a slipper wrench.

In some embodiments, a soft tentacle can include multiple sections offluidic channels along the length of the tentacle. FIGS. 15A-15Dillustrate a design and fabrication of a multi-section soft tentacle inaccordance with some embodiments of the disclosed subject matter. When atentacle has single-section fluidic channels (e.g., fluidic channelsrunning from the head-end of the tentacle to the tail-end of thetentacle), the tentacle can have a single bending mode, as illustratedin FIGS. 2A-2E, 4A-4F, and 14A-14G. However, when a tentacle hasmulti-section fluidic channels, the tentacle can have additional bendingmodes, which can allow for complex motions. In some embodiments, two ormore sectioned fluidic channels can be vertically aligned. For example,when a soft tentacle is held vertically (i.e., the longer dimensionalong the vertical axis), two or more sectioned fluidic channels can bealigned vertically.

FIG. 15C illustrates a four-section tentacle, where each section of thetentacle includes three fluidic channels arranged symmetrically aroundthe rotation axis. The four sectioned fluidic channels can be verticallyaligned. Each fluidic channel in each section can be controlledindependently using its own gas inlet. Since there are four sections andeach section has three fluidic channels, there are 12 independent gasinlets for the multi-section tentacle illustrated in FIG. 15D.Independent gas inlets allow for controlling each section of thetentacle independently, which can provide complex motions for thetentacle.

FIGS. 15A-15C illustrate a process for fabricating a multi-section softtentacle in accordance with some embodiments of the disclosed subjectmatter. The initial step includes providing a single-section softtentacle using, for example, the process illustrated in FIGS. 9A-9C. Thesecond step includes, as illustrated in FIG. 15A, creating smallchambers 1502 in the fluidic channels. The chambers 1502 can bedecoupled from the rest of the fluidic channels. In some embodiments,creating the chambers 1502 can include wrapping zip ties around acircumference of the tentacle. When the circumference of the tentacle isfirmly wrapped by two zip ties, the volume between the zip ties can formthe chambers 1502.

The third step includes, as illustrated in FIG. 15B, filling up thechambers 1502 using a soft material. The soft material can besubstantially identical to the soft material used to form the skinstructure of the tentacle. In some embodiments, the soft material caninclude Ecoflex prepolymer. In some embodiments, filling up the chambers1502 can include delivering the soft material to the chambers 1502 usinga syringe. The subsequent step can include curing the delivered softmaterial at 60° C. for 15 minutes to form strong walls between thefluidic channel sections. The fourth step includes, as illustrated inFIG. 15C, connecting tubings 1502 to the sectioned fluidic channels1504. In some embodiments, connecting tubings 1502 to the sectionedfluidic channels 1504 can include introducing the tubings 1502 to thetentacle via the core structure 208. Because the core structure 208 canbe formed using a stiffer material compared to the skin structure, thecore structure can bend, but may not expand. Therefore, by introducingthe tubings 1502 via the core structure 208, the tentacle's mobility canbe unhindered by the tubings 1502. FIG. 15D illustrates a cross-sectionof a multi-section tentacle in accordance with some embodiments of thedisclosed subject matter. The core structure 208, formed using PDMS,includes a plurality of tubings 1502 that are coupled to individualsections of the fluidic channels 1504.

The flexibility and deformability of a soft actuator provide complexmotions, even when the soft actuator is controlled using only few simpleon/off fluidic valves. FIGS. 16A-16D illustrate a variety of shapes thatcan be formed using a three-section soft tentacle in accordance withsome embodiments of the disclosed subject matter. Since each fluidicchannel section can be independently pressurized, the tentacle can adoptcomplex shapes.

A multi-section tentacle can be used in a variety of applications. Insome embodiments, the multi-section tentacle can be controlled tomanipulate delicate objects. Different sections of the multi-sectiontentacle can be inflated to grab an object and hold the object, asillustrated in FIGS. 16B-16D.

In some embodiments, a multi-section tentacle can move certain objectsin a predetermined path. In some cases, different sections in themulti-section tentacle can be responsible for certain types of motions.For example, a first section of the tentacle can be actuated to providea vertical movement; a second section of the tentacle can be actuated toprovide a planar movement; and a third section of the tentacle can beactuated to provide a gripping movement.

In some embodiments, a soft tentacle can be augmented with a transportchannel for transferring fluid and/or solid particles. The transportchannel can receive or deliver certain materials from one end of thetentacle to the other end of the tentacle. The transport channel can bea tubing embedded in the tentacle. In some embodiments, the transportchannel can be a tubing that is embedded in the core structure of thetentacle. In some embodiments, there can be two kinds of transportchannels: delivery channels and pumping channels. The delivery channelsare tubing that can flow gas, liquids, colloidal suspensions or aerosolsfrom a reservoir to the end of the tentacle. The channels to applyreduced pressure can pump liquids or solids through the length of thetentacle so they can be collected in a reservoir. Channels that applyreduced pressure (like vacuum-cleaners) cannot pump out solids with abigger diameter than the diameter of the channel, here we address thatproblem by dissolving the solid first, so the channel can pump out theliquid with the solid dissolved and the partially dissolved pieces ofsolid that now have a diameter smaller than the tubing.

In some embodiments, a soft tentacle with a transport channel canoperate as a fluid delivery robot. FIGS. 17A-17H illustrate anapplication of a fluid delivery robot for deactivating an electricalsystem enclosed in a polystyrene foam box in accordance with someembodiments of the disclosed subject matter. FIGS. 17A-17D illustrate asetup of the application. The electrical system 1702 in FIGS. 17A-17Bincludes a power unit (not shown), a light emitting diode (LED) 1704,and an electrical wire 1706. At an inactive state, as illustrated inFIG. 17A, the electrical wire 1706 disconnects the LED 1704 from thepower unit, such as a battery. However, at an active state, asillustrated in FIG. 17b , the electrical wire 1706 connects the LED 1704with the power unit. Therefore, the connection state of the electricalwire 1706 determines the state of the electrical system 1702.

This active electrical system is placed and enclosed in a polystyrenefoam box, as illustrated in FIGS. 17C-17D. The task for the fluiddelivery soft tentacle is to break into the polystyrene foam box and todeactivate the active electrical system. The fluid delivery softtentacle can accomplish the task by cutting the electrical wire 1706that connects the LED 1704 and the power unit.

FIGS. 17E-17H illustrate how the fluid delivery soft tentacle 1708performs the task. In FIG. 17e , the fluid delivery soft tentacle 1708positions its tail end so that it can deliver the liquid at a desiredposition on the box. Once the tentacle 1708 positions itself, thetentacle 1708 can receive liquid that can dissolve the box. For example,the tentacle 1708 can receive acetone from an external source anddeliver the acetone to the top of the box via the transport channel.FIG. 17F shows that the tentacle 1708 has dissolved a large portion ofthe box using the delivered liquid, creating a hole through which thetentacle 1708 can enter. In FIG. 17G, the tentacle 1708 uncurls itselfand enters the box through the open hole. Then the tentacle 1708 can cutthe electrical wire 1706 by pouring liquid that can dissolve theelectrical wire 1706. For example, the tentacle 1708 can pour theconcentrated nitric acid (HNO₃) on the electrical wire 1706. In FIG.17H, the tentacle 1708 finally dissolves the electrical wire 1706 usingthe acid, and cuts off the electrical connection between the LED 1704and the power unit. Because the electrical connection is cut off, theLED 1704 is turned off, indicating that the electrical system is nowdeactivated. FIG. 17E illustrates that the soft tentacle 1708 can beused in environments that are unsafe for physical human intervention.Furthermore, FIG. 17F illustrates that the soft tentacle 1708 can beused to deliver fluids that may be hazardous. While FIGS. 17G-17Hillustrates the application of a fluid delivery robot in a particularsynthetic scenario, the concept of using a fluid delivery robot fordismantling an electrical system can apply in a variety of scenarios,such as bomb dismantling and a hazardous area exploration.

In some embodiments, a soft tentacle with a transport channel cantransfer solid materials. FIGS. 18A-18D illustrate a transfer of solidmaterials using a soft tentacle in accordance with some embodiments ofthe disclosed subject matter. The soft tentacle with a transport channel1802 can be deployed to inhale solid materials 1806 on the petri dish.For example, one end of the transport channel 1802 can be coupled to asuction machine that can provide an air suction to inhale the softmaterials 1806. In some embodiments, the transport channel of thetentacle 1802 can be coupled, via a tubing, to a container 1804 that canreceive the inhaled solid materials. The container 1804 can be anErlenmeyer flask. The container 1804 can also be coupled to a suctionmachine (not shown) that can provide the air suction. The illustratedsystem can be used to inhale granular media, such as colored glassbeads, as illustrated in FIGS. 18A-18D.

In FIG. 18A, the tentacle 1802 is actuated to place the tail end of thetentacle 1802 on the solid materials 1806. This step can includeuncurling the soft tentacle 1802 by simultaneously actuating some of thesectioned fluidic channels. In FIG. 18B, the tail end of the tentacle1802 is placed on the target solid materials 1806. In FIG. 18C, thetentacle 1802 can start inhaling the solid materials 1806 through thetransport channel. The inhaled solid materials can be visually seen inthe container 1804. The tail-end of the tentacle 1802 can be actuated tomove around the petri dish to ensure that the tentacle 1802 inhales allthe solid materials 1806. In FIG. 18D, the tentacle 1802 can continue toinhale the solid materials 1806, until all of the solid materials 1806have been inhaled. Because the tentacle 1802 can move during the inhaleprocess, the tentacle 1802 can quickly inhale the solid materials spreadaround a sizeable area.

In some embodiments, a soft tentacle can time-multiplex its transportchannel. For example, the soft tentacle can use the transport channel todeliver fluid at a first point in time, and then use the same transportchannel to inhale solid particles at a second point in time.

In some embodiments, a soft tentacle can include a plurality oftransport channels. In some cases, each transport channel can betailored to perform a particular function. FIGS. 19A-19B illustrate asoft tentacle with a plurality of transport channels in accordance withsome embodiments of the disclosed subject matter. FIG. 19A illustrates across section of a soft tentacle 1902 with three transport channels. Thetransport channel 1904, embedded in the core structure, can be used totransfer air, and the other transport channels 1906, 1908 can be usedfor to transfer liquid. The liquid transport channels 1906, 1908 can beformed using two polyethylene tubes. FIG. 19B illustrates a delivery ofliquid via the liquid transport channels 1906, 1908.

In some embodiments, a soft tentacle 1902 with a plurality of transportchannels can be used to transfer sizeable solid particles. In somecases, the transport of large particles through the central transportchannel, as is illustrated in FIGS. 18A-18D, can be difficult due tofrequent clogging. For example, the transport of particles with adiameter greater than 1 mm can be challenging. To transport suchparticles, if the particles are soluble, the tentacle 1902 can firstdissolve the particles in liquid and then transfer the dissolvedparticles. This mechanism can be useful in reducing clogging.

In some embodiments, a soft tentacle can transport solid particles byeither dissolving the solid particles using liquid and transporting thedissolved solid particles or suspending the solid particles in theliquid. FIGS. 20A-20D illustrate a transfer of dissolved particles usinga soft tentacle in accordance with some embodiments of the disclosedsubject matter. As illustrated in FIG. 20A, the central transportchannel 1904 of the tentacle 1902 is coupled to a container 1804, andthe liquid transport channels 1906, 1908 of the tentacle 1902 arecoupled to a liquid source (not shown.) The container 1804 can be anErlenmeyer flask. The task for the tentacle 1902 is to transfer a pileof sodium chloride (NaCl) crystals 2002, having 1-3 mm, to the container1804.

In FIG. 20A, the tentacle 1902 can be actuated to place the tail end ofthe tentacle 1902 on the target particles 2002. In FIG. 20B, the sametentacle 1902 can deliver a solution (or water) to the target particles2002 via the fluid transport channels 1906, 1908 to dissolve the targetparticles 2002. In some cases, the delivered water can be warmed up to,for example, 60° C. to increase the solubility of the particles. In FIG.20C, while the tentacle 1902 delivers the water, the tentacle 1902 caninhale the dissolved particles via the air transport channel 1904. Insome cases, the tentacle 1902 can simultaneously deliver water andinhale the dissolved particles. In FIG. 20D, the tentacle 1902 caninhale the remaining residues and complete the transfer of the particles2002. In some cases, the solid particles may not dissolve entirely;instead, the solid particles may be suspended in the solution. Even inthose cases, the tentacle 1902 can inhale the suspending particles totransfer the particles from one location to another.

In some embodiments, a soft tentacle can cooperate with other roboticelements to provide additional functionalities. For example, thetentacle can be coupled with a suction cup. FIGS. 21A-21E illustrate asuction robot and its operation in accordance with some embodiments ofthe disclosed subject matter. As illustrated in FIG. 21A, the suctionrobot can include a soft tentacle 202 and a suction module 2102. Thesoft tentacle 202 can include a transport channel that can be used as asuction channel. The suction channel can be coupled to the suctionmodule 2102. The suction channel can allow an external pressure sourceto actuate the suction module 2102 by inhaling air through the suctionchannel. In some embodiments, the suction channel can be embedded in thecore structure. The suction channel can be controlled using a suctionchannel inlet 2104 connected to a mechanical pump, vacuum lines, orother sources of reduce pressure; the fluidic channels in the tentacle202 can be controlled using motion channel inlets 206. The suctionchannel can be coupled to sources of gas (like a gas compressor) orsources of reduced pressure (like a mechanical pump, vacuum line, avacuum cleaner) for operation.

In some cases, the suction robot can be used to lift an object 2106,such as a liquid bottle, as illustrated in FIGS. 20B-20E. As illustratedin FIG. 21B, the soft tentacle 202 can be actuated to place the suctionmodule 2102 on the object 2106. As illustrated in FIG. 21C, once thesuction module 2102 is placed on the object 2106, the suction module2102 can be activated to couple the suction module 2102 tightly onto theobject 2106. As illustrated in FIG. 21E, the soft tentacle 202 can thenbe actuated so that the soft tentacle 202 curls itself, thereby imposinga lifting force on the object 2106. In some cases, the length to whichthe object 2106 is lifted can be controlled by controlling the pressureapplied to the soft tentacle 202. For example, as illustrated in FIG.21E, the soft tentacle can be actuated further to increase the liftingforce, thereby lifting the object 2106 higher.

A soft tentacle can cooperate with other elements to provide usefulfunctionalities for biomedical applications. For example, a doctor canuse the soft tentacle during a surgical procedure to provide water to atarget region in order to, for example, wash away blood clots. Thedoctor can also use the same tentacle to collect waste products duringthe surgical procedure either through the transport channel or bygrabbing the waste product via a rolling motion of the tentacle. In somecases, the doctor can use a soft tentacle with a plurality of transportchannels to provide water and collect waste products at the same time.In some cases, the doctor can use a multi-section soft tentacle tomaneuver around a region of interest and transport fluid from/to adesired location.

In some embodiments, a soft tentacle can include a camera module forcapturing image/video information. The soft tentacle with a cameramodule can be deployed as an endoscope for capturing image/videoinformation of body parts that are not easily accessible. For example, asoft tentacle-based endoscope can be used for colonoscopy oresophagogastroduodenoscopy. A soft tentacle-based endoscope has manyadvantages compared to a conventional endoscope. For example, due to itsgreat degree of bending, the soft tentacle-based endoscope can providecontrolled movements within the body, which is difficult with aconventional endoscope. Embedding functional components into theseactuators (for example, a video camera, tubing for delivering fluid, ora suction channel) would extend the capabilities of these softendoscopes. Furthermore, the soft tentacle is inherently soft and can beless intrusive during operation. The elastomeric skin of soft tentaclesis chemically resistant to a variety of solvents, basis, and acids, whatmake these endoscopes more suitable than the traditional hose endoscopesfor their use in chemically aggressive media such as the digestive tractor harsh industrial inspection environments.

The central channel of the soft tentacles can be used to host componentswith specialized optical, electrical, or mechanical functions. FIG. 22illustrates a soft tentacle with a camera module in accordance with someembodiments of the disclosed subject matter. The soft tentacle caninclude single-section fluidic channels or multi-section fluidicchannels. The camera module 2202 can be coupled to a tail-end of thetentacle. After the camera and its wires were introduced along thecentral channel of the tentacle the rest of the central channel wasfilled with elastomers so, after the elastomers cured, the camera movesas a whole with the soft-tentacle. The camera module 2202 can be acharge coupled device (CCD) image sensor or a complementarymetal-oxide-semiconductor (CMOS) image sensor. The camera module 2202can be coupled to a computer and/or a power unit via an electrical wire.In some embodiments, the electrical wire can be embedded in the corestructure of the tentacle. For example, the electrical wire can beinserted along the central channel and glued in place with PDMS. Toavoid damage to the video camera from the thermal curing step, the PDMSwas cured at room temperature for 48 hours.

In some embodiments, the soft tentacle can include two sections. Thesection of the tentacle closest to the tether can bend to form a base ofthe tentacle so that the other section with a camera module 2202 can belifted out of plane and be oriented in a desired direction.

In some embodiments, the soft tentacle having a camera module 2202 canbe mounted on a soft robot to provide vision to the soft robot. The softtentacle can be configured so that the camera module 2202 can beoriented in any desired direction. FIGS. 24A-24D shows a soft-tentaclemounted on a soft robot in accordance with some embodiments of thedisclosed subject matter. FIGS. 24A-24D includes a quadruped soft robot2402 and a soft-tentacle 2404 having a camera module. The quadruped softrobot 2402 can include a plurality of actuators that can beindependently actuated via pressurization, and the soft tentacle 2404can include a camera module 2202. As illustrated in FIGS. 24A-24D, thequadruped soft robot 2402 and the soft tentacle 2404 can be actuatedindependently. This allows the soft tentacle to provide an almost 360°vision to the quadruped soft robot 2402.

In some embodiments, a soft tentacle can include an apparatus forperforming certain surgical procedures on a patient. The apparatus caninclude scissors, a knife, a clamp, a clip, a decapitator, forceps, amicrodissector, a scalpel, a tweezer, or a needle. As a particularexample, FIG. 23 illustrates a soft tentacle that includes a hypodermicneedle (22 G11/2) for fluid delivery in accordance with some embodimentsof the disclosed subject matter. The hypodermic needle was connected tothe end of a polyethylene tubing, then the ensemble was introducedthrough the central channel of the tentacle. The central channel wasfilled with elastomers to secure the fluid delivery channel. The needle2302 can be coupled to a transport channel of the tentacle. Therefore,the need 2302 can be used to deliver a desired amount of fluid to adesired location. For example, a doctor can use the soft tentacle tomove the needle 2302 to a desired location, and use the needle 2302 todeliver a desired amount of fluid to a desired location.

Radial Deflection Actuators

Some embodiments of a radial deflection actuator can include a softmaterial with an embedded network of fluid channels (e.g., pneumaticnetworks.) Such soft robotics include fluidic channels that are disposedradially around a central point, which causes the robot to deflectupwards out of the plane that houses the channels when at rest. In someembodiments, the channels form arced channels having a radius ofcurvature around an imaginary central point in the device. In someembodiments, the channels forms arcs, semi-circles, circles and thelike, arranged around a central point in the device. When pressurizedwith fluids, the radially positioned fluid channels can inflate todeflect the actuator into a hemispherical geometry, thereby providing aradial deflection to the actuator.

FIGS. 25A-25C illustrate a radial deflection actuator in accordance withsome embodiments of the disclosed subject matter. The top view of aradial deflection actuator 2500, illustrated in FIG. 25A, showsfluid/fluidic channels 2502 embedded in a flexible body 2504. Theflexible body 2504 can be formed using a soft material. In thisparticular embodiment, the radial channels 2502 are arranged inconcentric circles; however, as noted above, the channels can have othershapes and arrangements radially arranged around a central point. Thefluid channels 2502 is sealed from the bottom (not shown) using aflexible, but relatively inextensible layer. This layer isstrain-limiting with respect to the soft material covering the top layerof the fluid channels 2502.

FIG. 25B illustrates a cross-section of the radial deflection actuator,in accordance with the embodiment disclosed in FIG. 25A. The illustratedcross-section is taken along the dotted line 2506. The cross sectionillustrates the fluid channels 2502 and the flexible body 2504, the toplayer 2508 of the fluid channels 2502 formed using the same softmaterial as the flexible body 2504, and the strain limiting layer 2510sealing the fluid channels 2502. FIG. 25B illustrates the radialdeflection actuator 2500 in a relaxed state. The relaxed state is astate in which the pressure in the fluid channels 2502 is substantiallysimilar to the ambient pressure, P_(amb), as in FIG. 1A. Because thefluid channels 2502 are not pressurized, the actuator 2500 lies flat andis not deflected.

FIG. 25C illustrates a cross-section of the radial deflection actuatorin a pressurized state, in accordance with the embodiment disclosed inFIG. 25A. Again, the cross-section is taken along the dotted line 2506.In some embodiments, the fluid channels 2502 can be pressurized througha pressurizing inlet 2512, indicated by ‘X.’ However, the pressurizinginlet can be located anywhere. When the fluid channels 2502 arepressurized, the fluid channels 2502 inflates the top layer 2508 andbend around the strain limiting layer 2510. Because this bending motionis provided along every radial cross sections, the actuator 2500deflects into a convex or hemispherical geometry, thereby providing aradial deflection to the actuator 2500.

In some embodiments, the fluid channels 2502 can be arranged indifferent shapes and still provide radial deflection movements. In someembodiments, the channels form arced channels having a radius ofcurvature around an imaginary central point in the device. In someembodiments, the channels forms arcs, semi-circles, circles and thelike, arranged around a central point in the device. For example, thefluid channels can be arranged as concentric triangles, concentricsquares, concentric pentagons, and any other concentric polygons. Whenthe polygon formed by the fluid channels is equilateral, the radialdeflection movement is isotropic; when the polygon is non-equilateral,the radial deflection movement is non-isotropic.

In some embodiments, channels in materials such as used herein can befabricated by using soft lithography. Forming channels in silicones andother elastomers is a well understood, widely used technique in softlithography and microfluidics and can be applied to the construction ofsoft robotic pressurized networks.

In other embodiments, the actuator 2500 can be molded. The pressurizablenetworks are prepared by casting the elastomeric materials in a moldcontaining the negative replica of the desired features in thestructure. FIG. 26 illustrates a mold for molding the radial deflectionactuator in accordance with the embodiment of FIGS. 25A-25C. The molddefines the “negative” structure of the actuator 2500. For example, theraised walls 2602 define the volume for fluid channels 2502 and thetrenches 2604 formed by the raised walls 2602 define the volume for theflexible body 2504. Also, the raised structure 2606 coupled to theraised walls 2602 can form the conduit for providing pressurized fluid.By casting a soft material in this mold, a flexible molded body 2504with embedded fluid channels 2502 can be provided. Once the softmaterial is molded into a flexible molded body 2504, the flexible moldedbody 204 can be sealed using a strain-limiting layer 2510 as disclosedin FIGS. 25A-25C in accordance with some embodiments of the disclosedsubject matter.

Such methods of manufacture permit fabrication of devices having anoverall thickness greater than 1 mm and typically having a thickness inthe range of 5 mm to 5 cm. Exemplary thicknesses include 2-4 mm, 5 mm, 1cm, 2 cm, or 5 cm. The relatively large scale of the pressurizablenetworks (compared to features obtainable, for example, by conventionalphotolithographic techniques) result in the fabrication of functionaldevices on a large scale. Embedded channel networks in soft robotics arenot limited to large scale and it is contemplated that conventionalmicrofabrication techniques can be used to develop soft robotics on thesub-millimeter scale.

In some embodiments, the radial deflection actuator 2500 can be used asa gripping device by creating a suction or negative pressure between thedevice and the gripped surface. FIGS. 27A-27C illustrate using theradial deflection actuator as a gripping device in accordance with someembodiments of the disclosed subject matter. First, the actuator 2500can be placed in contact with an object 2702 that is non-porous, as inFIG. 27A. Then, the actuator 2500 can be pressurized and inflated as inFIG. 27B. While only shown in cross-section, the radial distribution ofthe fluidic channels around a central point causes the actuator todeflect upwards in two dimensions to form a ‘bubble’ or convex shapewith respect to the object. The conformal, sealing contact between thebottom layer of the actuator 2500 and the surface of the object 2702while pressurized creates the void space 2704 between them. The voidspace has a lower pressure than the external ambient pressure (indicatedby the notation that “ΔP=−”). This sub-atmospheric pressure holdstogether the bottom layer of the actuator 2500 and the surface of theobject 2702, providing the gripping. Thus, the actuator can function asa suction cup, that is, an object that uses negative fluid pressure ofair or water to adhere to a nonporous surfaces. Once this vacuum isformed, the actuator 2500 can lift the object 2702, as illustrated inFIG. 27C. This suction mechanism of the radial deflection actuator 2500can be useful in many applications. For example, the radial deflectionactuator 2500 can reversibly attach to objects for lifting or transferor anchor points for various components of machines. The actuator 2500can also be used to reliably control and maintain the position ofinstruments (e.g., cutting tools) or sensors. When placed at contactpoints between a robot and a surface, the actuator 2500 can also providea traction mechanism. In this regard, actuator 2500 can act as a ‘foot’for a soft robotic. In addition, the actuator 2500 can provide simplegripping and manipulation of delicate objects that may otherwise bedifficult to handle, for example, glass panes and sheets of paper orplastic.

FIGS. 28A-28C demonstrate a manipulation of an object, e.g., a petridish, using a radial deflection actuator in accordance with someembodiments of the disclosed subject matter. In this demonstration, theactuator 2800, substantially similar to the embodiment described inFIGS. 25A-25C, is pressurized via two conduits 2802. In FIG. 28A, theactuator 2800 is brought in contact with the petri dish 2804. At thispoint, the actuator 2800 is in a relaxed state, as illustrated in FIG.27A. In FIG. 28B, the actuator 2800 is pressurized so that the lowersurface of the actuator 2800 grips the petri dish 2804, as illustratedin FIG. 27B. In FIG. 28C, the actuator 2800 can be lifted to lift thepetri dish 2804 attached to actuator 2800.

The radial deflection actuator can cooperate with other robotic elementsto provide new functionalities. One of the new functionalities includesfluid control. For example, the radial deflection actuator can controlfluid flows in another robot. In particular, the radial deflectionactuator can be combined with a second chamber for the sampling anddelivery of fluids from one location to another, effectively forming afluid suction device. FIG. 29A illustrates a cross-section of a fluidsuction device in accordance with some embodiments of the disclosedsubject matter. The fluid suction device 2900 can include the radialdeflection actuator 2500, substantially as described in FIGS. 2A-2E, anda soft chamber 2902 stacked on the actuator 2500. The soft chamber 2902can include a reservoir 2904 that can accommodate fluids, such as gasesand liquids. The soft chamber 2902 can further include a fluid inlet2906 through which the soft chamber 2902 can receive or eject fluid. Thefluid inlet 2906 is not coupled to any of the fluid channels 2502.

In some embodiments, the soft chamber 2902 is provided on the radialdeflection actuator 2500 by attaching a cap on top of the radialdeflection actuator 2500. The cap can include a cover layer and one ormore walls, and the one or more walls are attached to the flexible body.The volume between the cap and the top of the radial deflection actuator2500 can form the reservoir 2904. In some cases, the cap can simply be alayer of soft material disposed on the radial deflection actuator 2500.The soft material of the soft chamber 2902 can be the same material asthat of the actuator 2500; the soft material of the soft chamber 2902can be a different soft material compared to that of the actuator 2500.

In some embodiments, the cap of the soft chamber 2902 can be molded.FIG. 30 shows a mold for molding a cap of the soft chamber 2902 inaccordance with the embodiment of FIGS. 29A-29D. The mold defines the“negative” structure of the layer for the soft chamber 2902. Forexample, the raised bump 3002 defines the reservoir 2904, the trench3004 defines the layer's wall for coupling the molded layer to theradial deflection actuator 2500, and the raised structure 3006 coupledto the raised bump 3002 defines the fluid inlet 2906 for the reservoir2904.

This fluid suction device shown in FIGS. 29A-29D can be used to collectand deliver fluids. FIGS. 29A-29D illustrate a fluid control mechanismof the soft fluid suction device in accordance with some embodiments ofthe disclosed subject matter. The fluid suction device 2900 illustratedin FIG. 29A is in its relaxed state. In the relaxed state, the radialdeflection actuator 2500 is in its relaxed state. FIG. 29B shows thefluid suction device in its exhaled state. In the exhaled state, theradial deflection actuator 2500 is actuated, which causes the radialdeflection actuator 2500 to radially deflect. Upon deflection, actuator2500 is disposed upward and into soft chamber 2902. The deflectedactuator 2500 reduces the volume of the reservoir 2904 in the softchamber 2902 and the soft chamber 2902 of the fluid suction device 2900“exhales” the air in the reservoir 2904 via the fluid inlet 2906.

When the actuator 2500 returns to its relaxed state, as in FIG. 29C, thevolume of the reservoir 3004 in the soft chamber 3002 returns to itsoriginal volume as well. As the actuator 2500 returns to its relaxedstate, the soft chamber 3002 is configured to “inhale” a volume of gas(air) or fluid via fluid inlet 3006. By placing the fluid inlet 3006 ina fluid, the soft chamber 3002 can inhale the desired fluid via thefluid inlet 3006. Thus, the device receives an aliquot of liquid intoreservoir 3004. To remove the fluid from reservoir 3004, the radialdeflection actuator 2500 can be re-actuated. Upon deflection, actuator2500 again is disposed upward and into soft chamber 3000. Again, thevolume of reservoir 3004 is compressed and in this way, soft chamber3002 delivers the captured fluid via the fluid inlet 3004 from thereservoir chamber.

As illustrated in FIGS. 29A-29D, the actuator 2500 provides an effectivemechanism for controlling the receipt and delivery of fluids in softchamber 2902. This fluid control mechanism can be useful in manyapplications. For example, the actuator 2500 provides a simple solutionto collecting and delivering fluids. In some embodiments, the actuator2500 can be coupled to other robots to sample fluids from a remotelocation (e.g., from harsh environments unsafe for humans) and deliverthe sampled fluid to another location. Because the sampled fluid can becompletely contained in the reservoir 2904, even toxic fluids can becollected and delivered safely.

FIGS. 31A-31D demonstrate a manipulation of dyed water using a fluidsuction device in accordance with some embodiments of the disclosedsubject matter. As disclosed in FIGS. 29A-29D, the fluid suction device3100 includes a radial deflection actuator 2500 and the soft chamber3102 stacked on top of the radial deflection actuator 2500. In thisdemonstration, the actuator 2500 is coupled to a pressure source via twoconduits 3104, and the soft chamber 3102 is coupled to the dyed watervia the fluid inlet 3106. In FIG. 31A, the fluid suction device 3100 isin its relaxed state, as illustrated in FIG. 29A. In FIG. 31B, theactuator 2500 is pressurized via the conduits 3104 so that the actuator2500 deflects radially. The radial deflection of the actuator 2500causes the soft chamber 3102 to exhale air in its reservoir. In FIG.31C, the actuator 2500 is depressurized to return to its relaxed state,which causes the soft chamber 3102 to inhale the dyed water, asdiscussed in FIG. 29C. The sampled dyed water can be retrieved bypressurizing the actuator 2500 again, as illustrated in FIG. 29D.

In addition to fluid collection and delivery, the fluid suction device3200 can be useful for localized chemical analysis and/or chemicalreaction. FIGS. 32A-32C demonstrate the use of the fluid suction device3200 in a chemical analysis application, in accordance with someembodiments of the disclosed subject matter. In this demonstration, thefluid suction device 3200 samples the chemical 3202 and deliverschemical 3202 into a reservoir housed within the soft chamber 3220, andaccommodates a chemical reaction in the reservoir for analyzing certaincharacteristics of the sampled chemical 3202. As shown in FIG. 32A, thefluid suction device 3200 is configured in a similar manner as in FIG.31A. For chemical analysis, the soft chamber 3220 in the fluid suctiondevice 3200 can include a colorimetric indicator, e.g., a colorimetricbase indicator. The translucent properties of silicone-based elastomers,such as Ecoflex silicone elastomers, make them particularly suitable forvisually observing the chemical reaction that takes place within thesoft chamber. In some embodiments, the colorimetric base indicator canbe a breakable capsule that is compressed upon actuation of actuator2500 to release the indicator material, e.g., a colorimetric baseindicator. In FIG. 32B, the fluid suction device 3200 is pressurized toexpel air residing in the reservoir of soft chamber 3220; upon return toits resting state (depressurization) fluid chemical 3202 is delivered toa reaction chamber within the soft chamber. The sampled chemical 3202reacts with the colorimetric base indicator, which would, in turn,indicate the characteristic of the sampled chemical 3202 using color, asillustrated in FIG. 32C. Because the fluid suction device 3200 istranslucent, the color change can be easily observed.

Hybrid Soft/Hard Robot

While soft robots can perform many types of complex motions, even themost sophisticated soft robots may be challenged by tasks that hardrobots can easily address. One such example is locomotion. Some softrobots can include a plurality of “soft actuator legs” that can be bentvia actuation. These soft robots can provide locomotion by bending thesoft actuator legs in a concerted manner, thereby providing aspider-like locomotion. Unfortunately, locomotive capabilities of suchmultifunctional soft robots may be limited and can fall short oflocomotive capabilities of hard robots, especially for certain terrains,such as flat terrains. While spider-like movements of soft robots can bewell equipped for moving on a rugged surface, such movements may not beable to provide rapid motion on flat surfaces. Therefore, robots thatretain desirable characteristics of both soft robots and hard robots aredesired.

FIG. 33 illustrates a robotic system in accordance with some embodimentsof the disclosed subject matter. The robotic system 3300 can include oneor more of the following components: a soft robot 3302, a roboticcontrol system 3304, a hard robot 3306, a camera system 3308, and acentral control system 3310. Each of these components are describedbelow in detail.

Soft Robot

In some embodiments, the soft robot 3302 can include one or moreactuators 3312. The actuators 3312 can include one or more fluidicchannels that can be actuated to provide motion. As a method ofactuation, most of the proposed soft robots utilize the reversiblechange in shape produced in thin, elastomeric membranes by pressure:microfluidic networks of channels embedded in soft elastomers can bedesigned to be used as actuation layers of stiffer elastomericmembranes. Channels are embedded into a softer elastomer and this layeris bonded to a stiffer, but still pliable layer. Upon pressurization ofthe channels using air (pneumatic actuation) or more generally a fluid(fluidic actuation), the soft elastomeric network expands. Thisexpansion, or strain, is limited at the interface between the softer andstiffer elastomeric layers; the expansion of the soft elastomer isaccommodated by bending around the stiffer, strain-limiting layer.

The actuators 3312 are configured to provide certain functionalities. Insome embodiments, the actuators 3312 can include a soft tentacleactuator 202. In other embodiments, the actuators 3312 can include theradial deflection actuator 2500. In yet other embodiments, the actuators3312 can include one or more of the actuators as disclosed in PCT PatentApplication No. PCT/US2011/061720, titled “Soft Robotic Actuators,” PCTPatent Application No. PCT/US2012/059226, titled “Systems and Methodsfor Actuating Soft Robotic Actuators,” PCT Patent Application No.PCT/US2013/028250, titled “Apparatus, System, and Method for ProvidingFabric-Elastomer Composites as Pneumatic Actuators” and PCT PatentApplication No. PCT/US2013/022593, titled “Flexible Robotic Actuators,”which are hereby incorporated herein by reference in their entireties.

In some embodiments, the actuators 3312 can be configured as a walker.FIG. 34 illustrates actuators configured as a walker in accordance withsome embodiments of the disclosed subject matter. The actuator 3312 caninclude legs that are configured to bend upon actuation. These legs canbe independently actuated to provide directional movements. FIGS.35A-35B illustrate the walking motion of the actuator 3312 in accordancewith some embodiments of the disclosed subject matter. FIG. 35Aillustrates that the actuator 3312 can walk up an inclined surface,having about 10-15 degrees of incline angle. FIG. 35B illustrates thatthe actuator 3312 can walk on a variety of surface types, includingsand.

In some embodiments, the actuator 3312 can be configured to exhibitrotational symmetry. For example, the actuator 3312 can have three legsconfigured to exhibit a three-fold rotational symmetry (i.e., C3symmetry.) The C3 symmetry configuration can provide a passive stabilityof the actuator 3312. In another example, the actuator 3312 can havefour legs configured to exhibit a four-fold rotational symmetry (i.e.,C4 symmetry.) This allows a simpler control of the actuator 3312 to movein multiple directions.

In some embodiments, each leg in the actuator 3312 can include twoparallel fluidic channels that can be independently actuated. Theparallel fluidic channels can run from the center of the actuator 3312to the tip of the leg and can act as agonist/antagonist muscles. Thispairing allows for actuating the leg in a paddling motion. FIGS. 36A-36Dillustrate the paddling motion of the leg in accordance with someembodiments of the disclosed subject matter. In FIG. 36A, both fluidicchannels are at an atmospheric pressure. When one of the fluidicchannels is pressurized, namely PN1, then the tip of the leg can moveforward-and-down, as illustrated in FIG. 36B. When both fluidic channelsare pressurized, the tip of the leg can move back-and-down, asillustrated in FIG. 36C. Subsequently, when the pressure in PN1 isremoved, then the tip of the leg can move back-and-up, as illustrated inFIG. 36D. When the pressure in both fluidic channels is removed, thenthe leg would return to the original position (not shown.) The sequenceof pressurization/depressurization of each of the eight fluidicchannels, (i.e., the fluidic channels of four legs) determines the gaitof the actuator 3312.

In some embodiments, the actuator 3312 can provide a rotational motion.For example, each leg in the actuator 3312 can be actuated with a slighttime-offset, which can provide an effective rotational motion to theactuator 3312. To facilitate the rotational motion, the tip of each legin the actuator 3312 can be made round. This allows the legs to remainin contact with the substrate when the actuator 3312 is rotated. In someembodiments, the legs in the actuator 3312 can be simultaneouslyactuated to operate as a gripper.

In some embodiments, the soft robot 3302 can include sensors 3314, asshown in the schematic in FIG. 33. The soft robot 3302 can use sensors3314 to gather information about its surroundings and respond to thegathered information. In some embodiments, sensors 3314 can include abump sensor. The soft robot 3302 can use the bump sensor to detectobstacles, and avoid the detected obstacles by moving around them. Abump sensor can include piezo-resistive sensors that change resistancewhen brought into contact with another object. This change in resistancecan be detected by the robotic control system, which would then causethe soft robot to alter the motion direction.

FIGS. 37A-37C illustrate the design and the deployment of a bump sensorin accordance with some embodiments of the disclosed subject matter.FIG. 37A illustrates a net 3702 for paper-based bump sensors. Thestencil printed carbon ink patches 3704A-3704D at four ends of the netcan operate as piezo-resistive sensors. Copper wires can be connected tothe piezo-resistive sensors 3704A-3704D using silver epoxy. FIG. 37Bshows the folded form of the bump sensor 3706, showing the triangularcross section of the arm and the top-side of the flexible hingecontaining the piezo-resistive sensors 3704A-3704D. When the flexiblehinge contacts another object, the resistance of the associatedpiezo-resistive sensor would change accordingly. The robotic controlsystem 3304 can detect this change in resistance and, in response, steerthe motion direction of the soft robot.

FIG. 37C shows how the bump sensor 3706 can be mounted on a soft robot3302. In some embodiments, the bump sensor 3706 can be mounted onto thesoft robot 3302 by gluing the bump sensor 3706 onto the soft robot 3302.The origami paper structure of the bump sensor 3706, having a triangularcross section, provides a rigid support and the flexible hinge providesthe scaffold for the stencil printed sensors. In the illustratedembodiment, both the bump sensor and the soft robot measure six inchesfrom point to point through their centers.

Robotic Control System

The robotic control system 3304 is coupled to the soft robot 3302, thehard robot 3306, and the central control system 3310. The roboticcontrol system 3304 can operate as a control center for controlling theoperation of the soft robot 3302 and the hard robot 3306.

In some embodiments, the robotic control system 3304 can include twomain elements: an electronic system and a fluidic system. The electronicsystem can include a control program module 3316 and a communicationlink module 3318. The control program module 3316 can communicate withthe hard robot 3306 via a wired serial bus and with the central controlsystem 3310 via the communication link module 3318. The communicationlink module 3318 can include a XBee wireless link module. The controlprogram module 3316 can implemented using a microprocessor, such asAtmel AVR 2056.

The control program module 3316 can receive an instruction to move thesoft robot 3302. For example, the control program module 3316 canreceive the instruction from a central control system 3310. The controlprogram module 3316 can use this instruction to determine how to controlthe soft robot 3302. In some cases, the control program module 3316 canreceive the instruction from a user via a central control system 3310.For example, a user can use a gamepad, coupled to the central controlsystem 3310, to specify the desired motion of the soft robot. Thecentral control system 3310 can process the user input and provideappropriate instruction to the control program module 3316. This allowsa semi-autonomous control of the robot's motion. In some embodiments,the control program module 3316 can receive sensory feedback informationfrom the sensors 3314 on the soft robot 3302. The control program module3316 can use this sensory feedback information to determine how toadjust the soft robot movements.

The fluidic system of the robotic control system 3304 can includefluidic pumps and valves 3320. The fluidic pumps and valves 3320 can becoupled to the soft robot 3302 to actuate the fluidic channels in thesoft robot 3302. In some embodiment, each of the fluidic pumps andvalves 3320 can be coupled unique fluidic channels. This allows therobotic control system 3304 to actuate fluidic channels independently,thereby enabling complex motions.

FIGS. 38C-38D illustrate the fluidic pumps and valves in accordance withsome embodiments of the disclosed subject matter. The fluidic pumps andvalves 3320 can include diaphragm pumps and solenoid valves that arerepurposed from low-cost sphygmomanometers. The schematic of thediaphragm pumps and solenoid valves is shown in FIG. 38D. FIG. 34 alsoillustrates how the diaphragm pumps and solenoid valves are coupled tothe soft robot 3312 in accordance with some embodiments of the disclosedsubject matter. In some embodiments, the pumps and valves 3320 can becontrolled using a custom built PCB and an open source, inexpensive,Arduino microcontroller. The microcontroller, pumps, and valves can runfrom a lithium-polymer battery so that the robotic system is portable.

In some embodiments, the fluidic pumps and valves 3320 can include anon-board, soft micro-pumping system, as disclosed in PCT PatentApplication No. PCT/US2012/059226, titled “Systems and Methods forActuating Soft Robotic Actuators,” which is herein incorporated byreference in its entirety. Different designs of micropumps arecontemplated, such as a micro-air compressor, a micro electrolyzer cell,and peroxide fuelled gas generator.

In some embodiments, the micropump can include a reciprocating diaphragmmicropumps such as those available from Takasao Electronics, e.g.,SDMP302 standard series piezoelectric micropump, with the smallestdevices on the order of 3000 mm³. These piezoelectrically actuatedmicropumps use less than a Watt of power to produce ˜1 mL/min air flowat ˜1 kPa. A soft 100 mm³ micropump is proposed by incorporatingexisting reciprocating diaphragm technologies into an embeddedelastomer. The air compressor can be composed of a diaphragm pump, inletand outlet membrane valves, and micro air channels. The complete systemcan be assembled by bonding pre-patterned layers of silicone andpolyurethane elastomers. The only rigid component in the assembly is theelectrically powered actuator used to pump the air chamber.

In some embodiments, the micropump can include an electrolyzer cell thatcan produce gas. The electrolyzer cell can generate gas (hydrogen andoxygen) at the rate ˜5 mL/min, which is about 10˜50 times lower thandesired for the soft robots, however, improved performance is possibleby increasing voltage applied, the surface area of the electrodes, theconductivity of the aqueous solution, and combination of the above. Insome embodiments, the micropump can include a generator that generatespressure through catalyzed decomposition of hydrogen peroxide andself-regulated. Such a pump can produce stable pressure as high as 22psi, and be capable of drive the locomotion of a pneumatic rolling belt.

The control program module 3316 can control the pumps and valves 3320using actuation sequences. The actuation sequences can determine themotion of the soft robot. In some embodiments, the control programmodule 3316 can empirically determine the actuation sequences. Forexample, the control program module 3316 can find the control sequencefor the soft robot 3302 in a trial-and-error manner in order todetermine the adequate control sequence for desired motions. In mostcases, the actuation sequence for each fluidic channel can be abstractedas follows: (a) closing a valve, (b) turning on the pump to inflate(i.e., pressurize) the fluidic channel, (c) turning off the pump whilekeeping the valve closed, and (d) opening the valve to deflate thefluidic channel. FIG. 38B illustrates the empirically derived actuationsequences for a spider-like locomotion of the actuator 3312 inaccordance with some embodiments of the disclosed subject matter. Insome embodiments, by slightly offsetting the actuation sequence of eachfluidic channel, a rotation of the leg, as measured at the tip, can beobserved.

In some cases, the actuation sequences can be represented as a timingmatrix. Each row of the timing matrix can include the actuation sequencefor each fluidic channel coupled to the robotic control system 3304. Thetop row of the timing matrix can be considered the primary actuationsequence that initiates the actuation of a primary fluidic channel att=0. Then the other rows of the timing matrix, associated with otherfluidic channels, can be considered secondary actuation sequences thatare defined with respect to the primary actuation sequence. In someembodiments, these secondary actuation sequences can be defined in termsof their timing matrix rotation from t=0. In other words, the secondaryactuation sequences can be considered the time-shifted version of theprimary sequence. For example, suppose that a primary actuation sequenceis 110000000. Then the secondary actuation sequences can be derived fromthe primary actuation sequence via a “left-shift” matrix rotation. The“left-shift” matrix rotation is the process of shifting each element ofa matrix to the left. In this process, the leftmost element is takenfrom the end of the matrix and inserted back at the first position onthe right. For instance, the primary actuation sequence 110000000rotated to the left by one spot becomes the secondary actuation sequence100000001.

In some embodiments, the direction of the walking motion can be modifiedby permuting rows of the timing matrix associated with a directionalwalking motion. In contrast to the locomotion of most quadruped animals,an actuator 3312 having a rotational symmetry does not need to rotate tochange the motion direction. Instead, the actuator 3312 can becontrolled using a modified actuation sequence to cause sideways orbackwards movement. This tactic can be thought of as redefining whichside of the robot is the “front”. For example, the permutation of thetiming matrix changes the primary fluidic channel associated with theprimary actuation sequence of the directional walking motion. Thiseffectively changes the frontal side of the walker.

FIGS. 38A-38B qualitatively illustrate the permutation of the timingmatrix in accordance with some embodiments of the disclosed subjectmatter. FIG. 38A illustrates a soft robot in accordance with someembodiments of the disclosed subject matter. The each leg has twoindependently actuated fluidic channels. The quadruped has been designedfor stability, locomotion and directional control. Polyethylene tubingwas inserted into the leg through which pressurized air can actuate theleg. If the orientation of the soft robot is defined such that theinitial left front and right front legs contain fluidic channels B3, B4,A1, and A2, then these fluidic channels can constitute the “front” ofthe soft robot. In this case, the first fluidic channel to be actuatedin the sequences for forward, left, backward and right locomotion areA1, A3, B1 and B3 respectively. If the robotic control system 3304decides to modify the direction of the walking motion, the controlprogram module 3316 can permute the rows of the timing matrix toeffectively redefine which fluidic channel is actuated first using theprimary actuation sequence. This would change the orientation of thesoft robot so that the new left front and right front legs containfluidic channels B1, B2, A3, and A4.

FIG. 39 illustrates the directional walking movements of the soft robotin accordance with some embodiments of the disclosed subject matter. Inthis figure, the soft robot 3302 starts in the lower left corner of thefigure and then walks to the upper left, upper right, and then lowerright. The numbered stars correspond to the initial orientation of therobot: left fore 3902, right fore 3904, left hind 3906, and right hind3908. The soft robot 3302 moves in different directions by reorientingthe effective front of the robot 3312—the robot 3312 itself does notphysically turn.

The software needed for implementing the robotic control system 3304 caninclude a high level procedural or an object-orientated language such asMATLAB®, C, C++, C#, Java, or Perl. The software may also be implementedin assembly language if desired. In some embodiments, the software isstored on a storage medium or device such as read-only memory (ROM),programmable-read-only memory (PROM), electrically erasableprogrammable-read-only memory (EEPROM), flash memory, or a magnetic diskthat is readable by a general or special purpose-processing unit toperform the processes described in this document. The processors caninclude any microprocessor (single or multiple core), system on chip(SoC), microcontroller, digital signal processor (DSP), graphicsprocessing unit (GPU), or any other integrated circuit capable ofprocessing instructions such as an x86 microprocessor.

Hard Robot

The hard robot 3306 can include hard robot sensors 3322, motorcontrollers 3324, and a microcontroller 3326. The hard robot 3306 can beequipped for locomotion. In some embodiments, the hard robotic systemcan act as a transporter hub. The hub can carry the batteries, pumps,valves, microcontrollers, and communications equipment. The use ofwheels or tracks, or any other hard-body means for providing locomotion,leverages the strengths of these two robust, high load bearing,mechanical elements. In some embodiments, the hard robot 3306 cancontain its own microprocessor and instruction set and control itselfautonomously. In other embodiments, the hard robot 3306 can becontrolled entirely by the microprocessor in the robot control system3304.

Camera System

The camera system 3308 can include a communication link 3328 and acamera module 3330. The camera module 3330 can include one or more imagesensors for capturing image or video information surrounding the roboticsystem 3300, and one or more motors for moving the image sensors inresponse to external inputs. The communication link 3328 can include awireless link that can enable the camera system 3308 to be operated at adistance from the central control system 3310. The camera system 3308can be operated by a user—using a control pad and video feedback—or by acentral control system 3310.

Central Control System

The central control system 3310 can include a machine vision module3332, a remote control program module 3334, and communication links 3336and 3338. The machine vision module 3332 running on the central controlsystem 3310 allows object identification, and control/feedback of theposition/timing of the deployment and actions of the soft robot. Thecentral control system 3310 can be a remote computer, including adesktop computer, a laptop computer, a tablet computer, or a smartphone. The software needed for implementing the central control system3310 can include a high level procedural or an object-orientatedlanguage such as MATLAB®, C, C++, C#, Java, or Perl. The software mayalso be implemented in assembly language if desired. In someembodiments, the software is stored on a storage medium or device suchas read-only memory (ROM), programmable-read-only memory (PROM),electrically erasable programmable-read-only memory (EEPROM), flashmemory, or a magnetic disk that is readable by a general or specialpurpose-processing unit to perform the processes described in thisdocument. The processors can include any microprocessor (single ormultiple core), system on chip (SoC), microcontroller, digital signalprocessor (DSP), graphics processing unit (GPU), or any other integratedcircuit capable of processing instructions such as an x86microprocessor.

Application

In some embodiments, the robotic system 3300 can be configured as arobotic mover. FIGS. 40A-40B illustrate a robotic mover in accordancewith some embodiments of the disclosed subject matter. The robotic mover4000 can include a soft robot 3302, a robotic control system 3304, and ahard robot 3306, and can couple to a camera system 3308 and a centralcontrol system 3310 (not shown.)

The robotic mover 4000 can be deployed to perform certain predeterminedtasks. FIG. 41 illustrates a process of moving an object using a roboticmover in accordance with some embodiments of the disclosed subjectmatter. In step 4102, the robotic mover 4000 can detect a target objectto be moved. The robotic mover 4000 can detect the object to be movedusing a sensor that is attached to a hard robot 3306. The sensor caninclude one or more of, for example, a physical bump sensor 4002, aproximity sensor such as an infrared proximity sensor, and atime-of-flight sensor including a sonar sensor. In step 4104, therobotic mover 4000 can take an image of the detected object using thecamera system 3308 and provide the image to the central control system3310. In step 4106, the central control system 3310 can process thereceived image and determine whether or not the robotic mover 4000should remove the detected object. To this end, the central controlsystem 3310 can use an image processing system and/or an objectrecognition system.

If the central control system 3310 determines that the robotic mover4000 does not need to move the detected object, then the robotic mover4000 can proceed to step 4102 until the robotic mover 4000 detectsanother object. If the central control system 3310 determines that therobotic mover 4000 should move the detected object, then the roboticmover can proceed to step 4108.

In step 4108, the robotic control system 3304 in the robotic mover canactivate the fluidic pumps and valves 3320 so that the soft robot 3302can grab the detected object. For example, the robotic control system3304 can provide an activation sequence to the fluidic pumps and valves3320, and in response, the fluidic pumps and valves 3320 can cause thesoft robot 3302 to walk to the detected object and grab the detectedobject. The inherent compliance of the soft robot 3302 can limit anydamage or pressure inflicted on the detected object and can allow thesoft robot 3302 to pick up objects without knowing the shape of theobject.

In step 4110, the robotic control system 3304 can send control sequencesto the hard robot 3306 so that the hard robot 3306 can drag the softrobot 3302 and the grabbed object to a desired location. This way, thegrabbed object can be rapidly moved to a desired location. In someembodiments, the robotic control system 3304 can autonomously operatethe hard robot 3306; in other embodiments, the robotic control system3304 can receive instructions, from the central control system, to movethe hard robot to a desired location. Once the soft robot 3302 isdragged to a desired location, the soft robot 3302 can unleash thegrabbed object, and return to its dock, inside the hard robot 3306.

In some embodiments, the hard robot 3306 can include a vacuum cleaner.In such embodiments, the robotic mover 4000 can be configured as arobotic vacuum cleaner. The robotic vacuum cleaner can use the softrobot 3302 to grab and remove objects that cannot be removed by thevacuum cleaner. Once the soft robot 3302 removes such objects, therobotic vacuum cleaner can use the hard robot 3406 to remove theremainder.

In some embodiments, the robotic system 3300 can be used as atransporting hub. For example, the hard robot 3306 can be used totransport functional materials, such as fuels, glues, and foams, and thesoft robot 3302 can be used to apply or make use of the functionalmaterials.

In some embodiments, the hard robot 3306 can assist soft robots in tasksthat soft robots are not well equipped to carry out. For example, thehard robot 3306 can be used to provide power to the soft robot 3302. Thepower can be in the form of pneumatics, hydraulics, or any other typesof fluidic power.

In other embodiments, the soft robot 3302 can provide the hard robot3306 additional means to interact with surroundings. For example, thesoft robot 3302 can gather objects from the surroundings, and the hardrobot 3306 can analyze the gathered objects, and provide the analysisresult to the central control system.

In some embodiments, the robotic system 3300 can be used as a roboticmarsupial system having a soft robot and a hard robot where the hardrobot operates as a hub of the robotic marsupial system and the softrobot is carried by the hard robot. In such robotic marsupial system,the soft robot 3302 provides means for the hard robot 3306 to interactwith a hazardous environment without actually entering the hazardousenvironment. For instance, the soft robot 3302 can be deployed for bombdisposal, or deployed in a radiation-contaminated orchemical-contaminated environments, while the hard robot 3306 is placeddistant from the hazardous environment. This can be a useful strategyfor preserving an expensive hard robot 3306 at the expense of a cheapersoft robot 3302. In another example, the soft robot 3302 can provideoperating means in regions that hard robots would fail. Hard robots canfail under certain circumstances, such as when deployed in a regionexposed to a high radiation, deep soft mud, puddles of corrosivechemicals, or arcing electrical components. However, soft robots canstill operate well in those regions. Therefore, the soft robots canprovide means for the robotic system to operate properly, even when hardrobots fail. In another example, the soft robots would provide hardrobots capabilities to work with delicate subjects, such as woundedpeople. In yet another example, hard robots can customize the softrobots to operate in certain dedicated environments.

Materials for Soft Robots

The list of materials that can be used with soft robots is extensive andencompasses elastomers such as latex, polyurethanes, polyacrylates,silicones, vulcanized rubber for the extensible materials, and fabricssuch as paper, Kevlar©, cotton, nylon, etc. for the strain limitingmembrane. An exemplary list of material combinations is shown inTable 1. Each combination provides for a varying degree of bending uponactuation, where the bending degree for the same channel materialincreases, e.g., greater deflection or smaller radius of curvature atthe strain limiting layer, with increasing difference in elasticmodulus/tensile modulus of the strain limiter. Other materials andmaterial combinations will be apparent to one of skill in the art.

TABLE 1 Channel Material Young's Strain Limiting Material ModulusYoung's Material (kPa) Material Modulus Ecoflex © silicone ~40 PDMS ~400kPa Ecoflex © silicone ~40 Paper >10 GPa Ecoflex © silicone ~40 Plasticsheet ~0.2 GPa for LDPE ~3 GPa for PET Ecoflex © silicon ~40 Wovenfiber >70 GPa for Kevlar mesh (fabric) PDMS ~400 Paper >10 GPa

The choice of materials, coupled with the design of the channels,determines the response of the device to pressure. The pressurenecessary to achieve a particular amplitude of actuation scales with thestiffness of the materials. Each combination provides a differentbehavior in bending, upon actuation: for the same channel geometry, thebending increases with increasing difference in elastic modulus betweenthe elastomer and the strain limiting fabric (or layer). Effects ofmaterial choices is demonstrated with respect to two silicone elastomers(polydimethylsiloxane (PDMS, Dow Corning Sylgard 184) and Ecoflex 00-30(a siloxane produced by Smooth-On; http://www.smooth-on.com)) becausethey are readily accessible, are easy to work with, bond well to eachother to form multilayer structures, and are relatively inexpensive.However, other suitable material combinations will be readily apparent.PDMS is transparent and has a Shore A hardness of 50. It is elastic andcan withstand repeated bending, but fractures above a maximum strain of150%. As a result, PDMS has a limited range of deformation, and issuited for the more rigid parts of a structure—parts that bend but donot stretch. PDMS can be used as the flexible component, as noted inTable 1, in combination with stiffer materials such as paper. Ecoflexsilicone is translucent and has a hardness below the Shore A scale. Itfractures above a maximum strain of 900%; it is more flexible than PDMS,and therefore, it is suitable for components with largerstrains/displacements (i.e., the layers of actuation). Because it is sosoft, Ecoflex silicone, if unsupported, will bend under its own weight(PDMS, much less so). Composite structures, comprising layers of PDMSand Ecoflex silicone, balance the rigidity of PDMS with the flexibilityof Ecoflex silicone for the desired function.

In other embodiments, the alternate materials are useful for thefabrication of devices. Composites using paper, textiles, carbon-,glass- or metal fiber as the stiffer material (or a material having ahigher tensile modulus) are possible. In other embodiments, stiffness isintroduced into a wall of the channel by introducing a reinforcing agentinto one wall of the channel. In other embodiments, one wall ischemically treated to increase its stiffness. By way of example, anelastomeric flexible polymer can be impregnated with a polymer precursorsolution, which is then cured in a predetermined pattern to form astiffer polymer.

Although the present disclosure has been described and illustrated inthe foregoing example embodiments, it is understood that the presentdisclosure has been made only by way of example, and that numerouschanges in the details of implementation of the disclosure may be madewithout departing from the spirit and scope of the disclosure, which islimited only by the claims which follow. Other embodiments are withinthe following claims.

1. A robotic system comprising: a soft robot comprising an actuatorcomprising a plurality of fluid channels, and a pressurizing inletcoupled to the plurality of fluid channels, wherein the pressurizinginlet is configured to receive a pressurized fluid to pressurize theplurality of fluid channels to cause a movement of the soft robot and arobotic control system coupled to the soft robot, wherein the roboticcontrol system is configured to provide the pressurized fluid to thepressurizing inlet, wherein the plurality of fluid channels is arrangedso that a bending direction of the actuator changes as a function of apressure level in respective fluid channels.
 2. The robotic system ofclaim 1, further comprising one or more pumps and one or more valvescoupled to the pressurizing inlet.
 3. The robotic system of claim 2,wherein each of the one or more pumps is coupled to one of the pluralityof fluid channels, and each of the one or more valves is coupled to oneor more of the plurality of fluid channels.
 4. The robotic system ofclaim 1, wherein the robotic control system is configured to actuate theactuator using an actuation sequence associated with the plurality offluid channels.
 5. The robotic system of claim 4, wherein in theactuation sequence, the pump and valve are selected to actuate,independently, the one of the plurality of fluid channels that the pumpand valve are coupled to.
 6. The robotic system of claim 1, wherein theactuator comprises multiple sections along the length of the actuatorand each section comprises one or more of the plurality of fluidchannels.
 7. The robotic system of claim 6, wherein each of the one ormore pumps is coupled to the one or more of the plurality of fluidchannels in one of the multiple sections, and each of the one or morevalves is coupled to the one or more of the plurality of fluid channelsin one of the multiple sections.
 8. The robotic system of claim 7,wherein each of the sections having the one or more of the plurality offluid channels in said section is independently actuated by the pump andvalve coupled to the one or more of the plurality of fluid channels insaid section.
 9. The robotic system of claim 1, wherein the actuatorfurther comprises a transport channel for transferring fluid and/orsolid particles.
 10. The robotic system of claim 9, wherein thetransport channel is a delivery channel.
 11. The robotic system of claim10, wherein the delivery channel comprises a tubing for delivering gas,liquids, colloidal suspensions, or aerosols from a reservoir to theactuator.
 12. The robotic system of claim 9, wherein the transportchannel is a pumping channel.
 13. The robotic system of claim 1, furthercomprising a suction channel.
 14. The robotic system of claim 13,wherein the suction channel is connected to a source of gas or a reducedpressure.
 15. The robotic system of claim 14, wherein the source of areduced pressure is a mechanical pump, a vacuum line, or a vacuumcleaner.
 16. The robotic system of claim 1, further comprising a cameramodule.
 17. The robotic system of claim 16, wherein the camera modulecomprises one or more image sensors for capturing image or videoinformation surrounding the robotic system.
 18. The robotic system ofclaim 16, wherein the actuator is configured to be actuated in responseto the image captured by the camera module.
 19. The robotic system ofclaim 1, further comprising one or more sensors.
 20. The robotic systemof claim 19, wherein the sensor is a bump sensor for detecting anobstacle.
 21. The robotic system of claim 1, further comprising a hardrobot coupled to the soft robot and configured to provide locomotion tothe robotic system.
 22. A method of operating a robotic system, themethod comprising: providing the robotic system according to claim 1;actuating the actuator using an actuation sequence by the roboticcontrol system.
 23. The method of claim 22, wherein the robotic controlsystem comprises one or more pumps and one or more valves.
 24. Themethod of claim 23, wherein the method further comprises at least onestep of (a) closing one of the one or more valves, (b) turning on one ofthe one or more pumps to pressurize one of the plurality of channels,(c) turning off the pump while keeping the valve closed, and (d) openingthe valve to deflate one of the plurality of the fluid channels,according to the actuation sequence.